Answer:
249.9
uhm.. correct me if im wrong
What sentence represents this equation? 912=15−x 912 is the same as a number decreased by 15. 15 decreased by 912 is the same as a number. A number is the same as the difference of 15 and 912. 912 is the same as 15 decreased by a number.
9 1/2 is the same as a number decreased by 15
I guess that's the right answer maybe i'm wrong if I am oh well
How would I simplify these expressions? (Pre-Calculus) I know that you are supposed to multiply all of these to do so, but every time I do that, I still get the wrong answer. My textbook says that these are the answers:
19: -15 + 8i
21: 8 + 6i
23: 34
25: 85
Could anyone explain how they got these answers? Mine are way off. Is the book just wrong? In #21, how would 3 times 3 equal 8 in the answer? Am I missing something?
Since you have the answers, I'll just show the steps on how to get there.
============================================================
Problem 19
[tex](1+4i)^2\\\\(1+4i)(1+4i)\\\\1*1 + 1*4i + 4i*1 + 4i*4i\\\\1 + 4i + 4i + 16i^2\\\\1 + 4i + 4i + 16(-1)\\\\1 + 4i + 4i-16\\\\(1-16) + (4i+4i)\\\\(1-16) + (4+4)i\\\\-15 + 8i\\\\[/tex]
Keep in mind that [tex]i = \sqrt{-1}[/tex] by definition. Squaring both sides leads to [tex]i^2 = -1[/tex]
In the second step, I used the idea that x^2 = x*x. Right after that, I used the FOIL rule to expand everything out.
============================================================
Problem 21
We could follow the same idea as problem 19, but I'll use a different approach.
[tex](A+B)^2 = A^2+2AB+B^2\\\\(3+i)^2 = 3^2 + 2*3*i + i^2\\\\(3+i)^2 = 9 + 6i - 1\\\\(3+i)^2 = 8 + 6i\\\\[/tex]
The formula on the first line is the perfect square binomial formula.
============================================================
Problem 23
The FOIL rule can be used if you want, but I'll use the difference of squares rule instead.
[tex](m+n)(m-n) = m^2 - n^2\\\\(3+5i)(3-5i) = (3)^2 - (5i)^2\\\\(3+5i)(3-5i) = 9 - 25i^2\\\\(3+5i)(3-5i) = 9 - 25(-1)\\\\(3+5i)(3-5i) = 9 + 25\\\\(3+5i)(3-5i) = 34\\\\[/tex]
It turns out that multiplying any complex number of the form a+bi with its conjugate a-bi will result in a purely real number (that has no imaginary part). More specifically: [tex](a+bi)(a-bi) = a^2+b^2[/tex]
============================================================
Problem 25
We could use the difference of squares rule again, but I'll show a different approach. This time using the distribution rule. The FOIL rule could also be used if you wanted.
[tex](6+7i)(6-7i)\\\\x(6-7i)\\\\6x-7xi\\\\6(x)-7i(x)\\\\6(6+7i)-7i(6+7i)\\\\6(6)+6(7i)-7i(6)-7i(7i)\\\\36+42i-42i-49i^2\\\\36-49(-1)\\\\36+49\\\\85\\\\[/tex]
I used x = 6+7i and the substitution property to help distribute. Lines 3 and 6 are where distribution is applied.
Which inequality is graphed below?
A- y<1/4x-1
B- y>1/4x-1
C- y<_ 1/4x-1
D- y>_ 1/4x-1
Step-by-step explanation:
It is represented by ,
=> y ≥ 1/4x -1
Help please (due today) plz hellpp i cant solve it plz dont write anything just for points plzz
Answer:
After reviewing the question you posted I have deduced that the correct answers are:
11) Max has $10.00. He earns $25.75 per lawn that he mows.
12) No. She is wrong. She did not group like terms correctly.
Step-by-step explanation:
11)
For 11) I first identified the independent variable of the equation, being "10".
And then the dependent variable of the equation, being "25.75". (The dependent variable of an equation will always be affected by the x)
I then looked at all the possible answers to see which one shared a independent variable of "10" and a dependent variable of "25.75".
The only possible answer that matches is Max has $10.00. He earns $25.75 per lawn that he mows.
This is because the only two possible answers that have "10" being a variable that does not change (independent variable) are:
--- "Max has $10.00. He earns $25.75 per lawn that he mows.
--- "Jon buys 10 toycars for $25.75 each"
However!
"Jon buys 10 toycars for $25.75 each" is an incorrect answer because it uses "10", although independent, as the x variable that affects the independent variable of "25.75".
12)
To find the correct answer for this question I simplified the equation from:
8t-15+3t = 11m-15
Into:
8t+3t-15 = 11m-15
Which further simplifies into:
11t-15 = 11m-15
Which then you can notice that the two equations are similiar indeed, however they do not share like terms. One equation has "t" as their term, and the other as "m" as their term. Thus they do not share any like terms and are not equivalent.
Original Price of a computer $2,600.00 Tax:6.4%
Integrate :
[tex]\red{\footnotesize\displaystyle\bf \int cos^3 4x\:\:dx}[/tex]
Recall the half-angle identity for cosine:
cos²(x) = 1/2 (1 + cos(2x))
Then we can rewrite the integrand as
cos³(4x) = cos(4x) cos²(4x) = 1/2 cos(4x) (1 + cos(8x))
So we have
[tex]\displaystyle \int \cos^3(4x) \, dx = \frac12 \int (\cos(4x) + \cos(4x)\cos(8x)) \, dx[/tex]
Next, recall the cosine product identity,
cos(a) cos(b) = 1/2 (cos(a - b) + cos(a + b))
so that the integral is equivalent to
[tex]\displaystyle \int \cos^3(4x) \, dx = \frac12 \int \cos(4x) \, dx + \frac14 \int (\cos(4x - 8x) + \cos(4x + 8x)) \, dx[/tex]
[tex]\displaystyle \int \cos^3(4x) \, dx = \frac34 \int \cos(4x) \, dx + \frac14 \int \cos(12x) \, dx[/tex]
Computing the rest is trivial:
[tex]\displaystyle \int \cos^3(4x) \, dx = \boxed{\frac3{16} \sin(4x) + \frac1{48} \sin(4x) + C}[/tex]
PlEase help you can edit the photo
Answer:
The ribbon costs 1.25 per meter
Step-by-step explanation:
5/4=1.25
Solve for w.
16w–w–12w–2w=13
w=
Answer:
w = win
Step-by-step explanation:
w=13
Answer:
w = 13
Step-by-step explanation:
16w - w = 15w
15w - 12w = 3w
3w - 2w = w
w = 13
What is (−47)−(−107)=?
please help
60
Step-by-step explanation:
(-47)-(-107)
(-47)-1(-107)
-47+107
=60
consider the following equation:
2x−6y=9
Determine if the given ordered pair, (2,1/2), satisfies the given equation
yes or no
Answer:
The solution to a system of linear equations is the ordered pair (or pairs) that satisfies all equations in the system. The solution is the ordered pair(s) common to all lines in the system when the lines are graphed.
Lines that cross at a point (or points) are defined as a consistent system of equations. The place(s) where they cross are the solution(s) to the system.
Parallel lines do not cross. They have the same slope and different y-intercepts. They are an example of an inconsistent system of equations. An inconsistent system of equations has no solution.
Two equations that actually are the same line have an infinite number of solutions. This is an example of a dependent system of equations.
Step-by-step explanation:
Solve the system of equations graphically.
3x + 2y = 4
−x + 3y = −5
Solution
Graph each line and determine where they cross.
The lines intersect once at (2, −1).
A graphic solution to a system of equations is only as accurate as the scale of the paper or precision of the lines. At times the point of intersection will need to be estimated on the graph. When an exact solution is necessary, the system should be solved algebraically, either by substitution or by elimination.
Substitution Method
To solve a system of equations by substitution, solve one of the equations for a variable, for example x. Then replace that variable in the other equation with the terms you deemed equal and solve for the other variable, y. The solution to the system of equations is always an ordered pair.
Example
Solve the following system of equations by substitution.
x + 3y = 18
2x + y = 11
Solution
Solve for a variable in either equation. (If possible, choose a variable that does not have a coefficient to avoid working with fractions.)
In this case, it's easiest to rewrite the first equation by solving for x.
x + 3y = 18
x = −3y + 18
Next, substitute (−3y + 18) in for x into the other equation. Solve for y.
2( 3y + 12x + y = 11
2(−3y + 18) + y = 11-------Substitute -3y + 18 in for
−6y + 36 + y = 11-------Distribute.
2(3y −5y + 36 = 11-------Combine like terms.
2(3y + 18−5y = −25-----Subtract 36 from both sides
2(3y + 18) + y = 5---- -Divide both sides by -5.
Then, substitute y = 5 into your rewritten equation to find x.
x = −3y + 18
x = −3(5) + 18
x = −15 + 18
x = 3
Identify the solution. A check using x = 3 and y = 5 in both equations will show that the solution is the ordered pair (3, 5).
Elimination Method
Another way to solve a system of equations is by using the elimination method. The aim of using the elimination method is to have one variable cancel out. The resulting sum will contain a single variable that can then be identified. Once one variable is found, it can be substituted into either of the original equations to find the other variable.
Example
Find the solution to the system of equations by using the elimination method.
x − 2y = 9
3x + 2y = 11
Solution
Add the equations.
x − 2y = 9
3x + 2y = 11
4x + 2y = 20
Isolate the variable in the new equation
4x = 20
x = 5
Substitute x = 5 into either of the original equations to find y.
x − 2y = 9
(5) − 2y = 9
−2y = 4
y = −2
Identify the ordered pair that is the solution. A check in both equations will show that (5, −2) is a solution.
It may be necessary to multiply one or both of the equations in the system by a constant in order to obtain a variable that can be eliminated by addition. For example, consider the system of equations below:
3x + 2y = 6
x − 5y = 8
Both sides of the second equation above could be multiplied by −3. Multiplying the equation by the same number on both sides does not change the value of the equation. It will result in an equation whereby the x values can be eliminated through addition.
Special Cases
In some circumstances, both variables will drop out when adding the equations. If the resulting expression is not true, then the system is inconsistent and has no solution.
4x + 6y = 13
6x + 9y = 17
3(4x + 6y = 13)
2(6x + 9y = 17)
12x + 18y = 39
12x + 18y = 34
0 = 5
The equation is false. The system has no solution.
If both variables drop out and the resulting expression is true, then the system is dependent and has infinite solutions.
6x + 15y = 24
4x + 10y = 16
2(6x + 15y = 24)
3(4x + 10y = 16)
12x + 30y = 48
12x + 30y = 48
0 = 0
The equation is true. The system has an infinite number of solutions. (Notice that both of the original equations reduce to 2x + 5y = 8. All solutions to the system lie on this line.)
4. At an Internet store, a laptop computer costs $724.99. At a local store, the same computer costs $879.95. What is the difference in prices?
Answer:
$154.96
Step-by-step explanation:
difference means to subtract so 879.95-724.99=154.96
b ÷ 0.52 for b = 6.344
Answer:
the answer is 12.2
[tex] \frac{b}{0.52} \\ we \: know \: b = 6.344 \\ then \\ \frac{6.344}{0.52} \\ = 12.2[/tex]
Fill in the blank with a number to make a true statement. *
0.25 / ? = -0.25
Which equations are true? Select all that apply.
A.
66
÷
10
1
=
6
.
6
B.
660
÷
10
0
=
66
C.
6
,
600
÷
1
,
000
=
0
.
66
D.
0
.
66
÷
10
1
=
0
.
066
E.
6
÷
100
=
0
.
06
Answer:
a b d e
Step-by-step explanation:
i just took the test and got a hundred
Equations A, B, and E are true, i.e 66: 10 = 6.6, 660: 10° = 66, 6: 100 = 0.06.
What is the equation?An equation is a statement that two expressions, which include variables and/or numbers, are equal. In essence, equations are questions, and efforts to systematically find solutions to these questions have been the driving forces behind the creation of mathematics.
Make sure your equation is correct by comparing the values on either side of the equals sign to create a true equation. A true equation must have the same numerical values on both sides of the "=" sign. One real equation is, for instance, 9 = 9. A valid equation is 5 + 4 = 9.
As a result, the true equations are,
66: 10 = 6.6
660: 10° = 66
6: 100 = 0.06
Thus, equations A, B, and E are true, i.e 66: 10 = 6.6, 660: 10° = 66, 6: 100 = 0.06.
Learn more about the equation here,
https://brainly.com/question/10413253
#SPJ2
help on math review edu
Answer:
Answer is A
Step-by-step explanation:
Subtract 47 from both sides to get 0
3x² - 18x - 42 = 0
Use Quadratic formula to get
[tex]3+\sqrt{23} \\3-\sqrt{23}[/tex]
Answer:
Step-by-step explanation:
Why we often leave radicals as roots without calculating them?
Answer:
Sometimes it's better to leave them as roots because it's easier sometimes to solve problems with them still as roots
Answer:
We choose to leave radicals as roots without calculating them because calculating the square roots of a non perfect squares result in an irrational, non terminating decimal.
Step-by-step explanation:
Why do we do Radicals in the first place?
Radicals are used to write the square root or the nth root of a number. We sometimes leave specific numbers (non-perfect squares) as a radical because the output would be infinity
Example:
[tex]\sqrt45[/tex] is not a perfect square, it lies between [tex]\sqrt36[/tex] and [tex]\sqrt49[/tex]
This means the number lies in between 6 and 7
The true root of 45 is irrational. Recall that irrational numbers are numbers of non-perfect squares. [tex]\sqrt45[/tex] = 6.7082039.......
Simplify:
[tex]\sqrt 45 = \sqrt 9 * \sqrt 5\\[/tex]
[tex]= \sqrt3^2 * \sqrt 5\\\\ \\= 3\sqrt5[/tex]
We choose not to pursue simplifying this because [tex]\sqrt5[/tex] is irrational (square root of a non-perfect square)
Summary:
We choose to leave radicals as roots without calculating them because calculating the square roots of a non perfect squares result in an irrational, non terminating decimal.
-Chetan K
1. If something gets 1 percent better each day, how long will it take it to become 100 percent better than it already is? Round to the nearest day.
2. How many times better will it be in 365 days? Round to the nearest percent.
Answer:
it would take 100 days for it to get better that just makes sense I think and for number two it would be 365% better
Step-by-step explanation:
The area of a triangular flower bed in the park has an area of
120 square feet. The base is six feet shorter than three times the height. What are the base and height of the triangle?
Answer:
b = 24 ft
h = 10 ft
Step-by-step explanation:
120 = ½hb
120 = ½h(3h - 6)
240 = h(3h - 6)
240 = 3h² - 6h
80 = h² - 2h
0 = h² - 2h - 80
0 = (h - 10)(h + 8)
h = 10 ft or -8 ft
we ignore -8 as it makes no sense for a triangle side length.
b = 3(10) - 6 = 24 ft
evaluate the expression 5+3
Answer:
8
Step-by-step explanation:
Answer:
8
Step-by-step explanation:
5 + 3 = 8
-Lexi
a square has an area of 64 square units. if it’s side were only half as long, what would it’s area be??
Answer:
16
Step-by-step explanation:
8x8 is 64, so half of 8 is 4 so 4x4 is 16
Jonas is conducting an experiment using a 10-sided die. He determines that the theoretical probability of rolling a 3 is StartFraction 1 over 10 EndFraction. He rolls the die 20 times. Four of those rolls result in a 3. Which adjustment can Jonas make to his experiment so the theoretical and experimental probabilities are likely to be closer?
A.He can decrease the sample space.
B.He can increase the sample space.
C.He can decrease the number of trials.
D.He can increase the number of trials.
Answer:
A. He can decrease the simple spacw
Answer:
D. He can increase the number of trials
NEED HELP ASAP (WILL GIVD BRAINELST)
Answer:
5
Step-by-step explanation:
The answer is 60/12 becuase we can simfly both of theese mixed numbers into an improper fraction, wich will be 4/3*15/4. We do the multiplication, and we get 60/12. 60/12 can be simplifed to 5 becuase 60 divided by 12 is 5
Find the value of x. Show all work.
(7x + 6)°
(6x - 7)º
Answer:
42x-42
Step-by-step explanation:
(7x)(6x)+(6)(-7)=42x°-42°
what is 4a-6b+9c + 5a+9b-3c
Answer:
9a + 3b + 6c
Step-by-step explanation:
4a-6b+9c + 5a+9b-3c
4a + (-6b) + 9c + 5a + 9b + (-3c)
(4a + 5a) + (-6b+9b) + (9c-3c)
9a + 3b + 6c
Answer:
the person below is correct I believe
Step-by-step explanation:
hope this helped have a good rest of your night :)❤
What is the answer =2^3(10-7)/3*7?
Answer:
the ansewer is 56
Step-by-step explanation:
by appling bodmas rule which means if such type of operation apper in one question we work it step by step first bracket then division next multiplication then addition finaly substruction 2^3(10-7)/3*7(10-7)=32^3(3)/3*73/3=12^3*1*72^3=88*1*7=8*7=56Help help help help help help
Answer:
b
gnzjfzjgzjxjgzfjsngdjgsjfzgjskzjtztjsgjd5uduajai
Ellen solved the equation x2−5=59 using the following steps.
Review her work carefully, and then follow the instructions.
Line 1: x2−5=59
Line 2: x2−5+5=59+5
Line 3: x2=64
Line 4: x=8
Which statement identifies a mistake Ellen made, if any?
Answer:
c
Step-by-step explanation:
In Line 4, she forgot to take the negative square root, because squaring both 8 and −8 equals 64.
A house has increased in value by 32% since it was purchased. If the current value is 561000 what was the value when it was purchased?
Answer:
$425000
Step-by-step explanation:
561000*100/132=425000
A teacher printed 730 copies how long did it take to print
Answer:
Can you provide how long it took to print per copy
Step-by-step explanation:
Answer:
it will take him 50 min because their are 730 and that is lot so it will take him 50min
Evaluate y=(-2)(x) + 4 when x=(-3).
Answer:
y = 10
Step-by-step explanation:
y = (-2)(x) + 4
y = (-2)(-3) + 4
y = 6 + 4
y = 10