how to factor 3y^2-6^2+9

Question

I need to be able to factor the expression above. I know that three goes into everything and I have to do that first but I don't know what to do from there.

Answer 1

First, combine like terms.

So, -6^2=-36

-36+9=27

 

This leaves you with 3y^2-27

 

Now divide it by the greatest common factor, which in this case is 3.

 

3(y^2 - 9)

 

3(y-3)(y+3)

Answer 2

Dylan, the second and third terms can be combined after evaluating the square of the second term. Hence,

 

3y^2-6^2+9=3y^2-36+9=3y^2-27=3(y^2-9)=3(y-3)(y+3)