1. Use the FOIL method (x+9)(x+9)
First, outer, inner, last

Add your like terms

2. When you add or subtract polynomials you add or subtract the like terms and then put them in order from largest to smallest exponents.
3.

4. Since it is the perimeter, we add the 3 together.

Add the like terms together:

Put them in order of exponents

Hope this helps
Answer:
yes
Step-by-step explanation:
just measure the things
<h3>
Answer: x = 3</h3>
To get that answer, we replace y with 8 and then isolate x.
5x-7 = y
5x-7 = 8
5x = 8+7
5x = 15
x = 15/5
x = 3