Question

How do you factor `x^2y^2 - 17xy^2 + 72y^2`?

Answer 1

Notice that all of the terms are multiples of `y^2`.

Also notice that `72 = 8 xx 9`, while `17 = 8 + 9`.

So:

`x^2y^2-17xy^2+72y^2`

`=y^2(x^2-17x+72)`

`=y^2(x-8)(x-9)`