a) (y – 7)^2 is the same as (y-7) * (y-7)

F: y* y = y ^ 2

O : y * -7 = -7y

I: -7 * y = -7y

L: (-7) * (-7) = 49

Now add all the terms up :

y^2 – 7y – 7y + 49 = y^2 – 14y + 49

You can follow the same steps to solve the others (lawllerzies gave you the correct answers with a few skipped steps so you can check your work there)

For the last problem they are really asking you to find a common term from both the numerator and the denominator that you can factor out

[x^2-9]/[5x+15]

Start with the numerator : x^2-9

Using the difference of two squares formula a^2 – b^2 = (a-b) (a+b) you can factor this

(Let a^2 = x^2 so a = x and let b^2 = 9 so b = 3)

x^2-9 = (x – 3 ) ( x + 3)

Now using the denominator: 5x+15

The GCF of each of the terms is 5 so factor out a 5

5x+15 = 5 ( x+ 3)

If you notice there is (x+3) in both the numerator and denominator. When you divide (x+3) by itself you get 1. (Just like 4/4 = 1)

You are then left with an answer of (x-3) / 5

Hope this helps!

y^2-14y+49

b) (2x + 9)(x – 2)

2x^2-4x+9x-18

2x^2+5x-18

c) (3x + 5)(3x – 5)

9x^2-25

[x^2-9]/[5x+15]

(x+3)(x-3)/5(x+3)

x-3/5

Good Luck!