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2 years ago

If a + b + c = -1, x + y = 7, what is -9a - 7x - 9c - 9b - 7y?

Mathematics

1 answer:

sineoko [7]2 years ago

6 0

Go on way math to find it.

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Survey data involving two random samples of students at law school are shown. The surveys were taken comparing the age of studen

Crazy boy [7]

Answer:

A and C if you don't believe me look at this link down below

Step-by-step explanation:

https://fsassessments.org/assets/documents/answer-keys-paper/FSA_2018_7M_Practice-Test_Answer-Key_PBT_Final.pdf

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2 years ago

Brett earns $19.20/h and he gets overtime for hours exceeding 40 per week.

Lubov Fominskaja [6]

Brett has to work 55 hours to make exactly $1056

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3 years ago

Read 2 more answers

PLZ HELP ME :( THIS IS DUE TOMMORW :((

Advocard [28]

It’s C. I hope this helps

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2 years ago

Derive these identities using the addition or subtraction formulas for sine or cosine: sinacosb=(sin(a+b)+sin(a-b))/2

Sergeu [11.5K]

Answer:

The work is in the explanation.

Step-by-step explanation:

The sine addition identity is:

$\sin(a+b)=\sin(a)\cos(b)+\cos(a)\sin(b)$ .

The sine difference identity is:

$\sin(a-b)=\sin(a)\cos(b)-\cos(a)\sin(a)$ .

The cosine addition identity is:

$\cos(a+b)=\cos(a)\cos(b)-\sin(a)\sin(b)$ .

The cosine difference identity is:

$\cos(a-b)=\cos(a)\cos(b)+\sin(a)\sin(b)$ .

We need to find a way to put some or all of these together to get:

$\sin(a)\cos(b)=\frac{\sin(a+b)+\sin(a-b)}{2}$ .

So I do notice on the right hand side the $\sin(a+b)$ and the $\sin(a-b)$ .

Let's start there then.

There is a plus sign in between them so let's add those together:

$\sin(a+b)+\sin(a-b)$

$=[\sin(a+b)]+[\sin(a-b)]$

$=[\sin(a)\cos(b)+\cos(a)\sin(b)]+[\sin(a)\cos(b)-\cos(a)\sin(b)]$

There are two pairs of like terms. I will gather them together so you can see it more clearly:

$=[\sin(a)\cos(b)+\sin(a)\cos(b)]+[\cos(a)\sin(b)-\cos(a)\sin(b)]$

$=2\sin(a)\cos(b)+0$

$=2\sin(a)\cos(b)$

So this implies:

$\sin(a+b)+\sin(a-b)=2\sin(a)\cos(b)$

Divide both sides by 2:

$\frac{\sin(a+b)+\sin(a-b)}{2}=\sin(a)\cos(b)$

By the symmetric property we can write:

$\sin(a)\cos(b)=\frac{\sin(a+b)+\sin(a-b)}{2}$

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3 years ago

1.07, 1.7 and 1.007 in order from<br><br>greatest to least

Vladimir [108]

1.7 , 1.07 , 1.007 greatest to least

4 0

2 years ago