What is the sum of the polynomials? (8x^2-9x^2-4x) + (x^2-3y^2-7x)

The sum of the polynomials is - 11x - 3y^2.

In order to find this we must first collect all like terms. To start, we'll begin with all x^2 terms.

8x^2 - 9x^2 + x^2 = 0

Since these all cancel, we're left with no x^2 term. Next we'll do x terms.

-4x - 7x = - 11x

The only thing left is - 3y^2, which has no alike term. so we just include that in there.

-11x - 3y^2