What are these types of factoring called?

Question

It's like factoring ax^2 + bx + c

except... ill give an example:

y^2 - 9

= (y-3)(y+3)

y^2 - 49

= (y-7)(y+7)

where.. it's so easy because all u have to do is find the sq of the number...

What are these called again?

Answer 1

perfect squares?

Answer 2

perfect factoring? I'm not really sure

Answer 3

It's just factoring.

Answer 4

that's called difference of squares

a^2-b^2=(a+b)(a-b)

there's also a sum of cubes formula

a^3+b^3=(a+b)(a^2-ab+b^2)

and a difference of cubes

a^3-b^3=(a-b)(a^2+ab+b^2)

there is no "sum of squares" formula,  as i'm sure you know. a sum of two squares is prime.