Answer:
21
Step-by-step explanation:
y = 3x + 9
y = -3x + 12
y=21

<h2>
Explanation:</h2>
In this exercise, we have the following functions:

And they are defined for all real numbers x. So we have to write the following expressions:
First expression:

That is, we subtract s(x) from r(x):

Second expression:

That is, we get the product of s(x) and r(x):

Third expression:
Here we need to evaluate:

First of all, we find the sum of functions r(x) and s(x):

Finally, substituting x = -2:

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Answer:
D
Step-by-step explanation:
Let's substitute a for x²:
x^4 - 3x² - 4
a² - 3a - 4
Now, this looks like something that is much more factorisable:
a² - 3a - 4 = (a - 4)(a + 1)
Plug x² back in for a:
(a - 4)(a + 1)
(x² - 4)(x² + 1)
The first one is a difference of squares, which can be factored into:
x² - 4 = (x + 2)(x - 2)
The second one can also be treated as a difference of squares:
x² + 1 = x² - (-1) = (x + √-1)(x - √-1) = (x + i)(x - i)
The answer is (x + 2)(x - 2)(x + i)(x - i), or D.
Answer:

Step-by-step explanation:
step 1
Find the length side PQ
we know that
The area of rectangle PQRS is given by


so

substitute the value of QR

solve for PQ

step 2
Find the length side AB
we know that
The perimeter of rectangle ABCD is given by

we have

substitute

solve for AB
