Question

Which expression can be used to find the sum of the polynomials? (9 – 3x2) (–8x2 4x 5)

Answer 1

For this case we have:

Polynomial 1: $P (x) = 9-3x ^ 2$

Polynomial 2: $Q (x) = - 8x ^ 2 + 4x + 5$

Sorting the polynomials:

Polynomial 1: $P (x) = - 3x ^ 2 + 9$

Polynomial 2: $Q (x) = - 8x ^ 2 + 4x + 5$

Adding term to term (similar) we have:

$P (x) + Q (x) = (- 3-8) x ^ 2 + (0 + 4) x + (9 + 5)\\P (x) + Q (x) = - 11x ^ 2 + 4x + 14$

Answer:

$A (x) = P (x) + Q (x) = - 11x ^ 2 + 4x + 14$

Answer 2

It seems that you missed the choices of the given question above. 
Anyway, here is the correct answer of the given polynomial above. The answer is [(-3x^2)+(-8x^2)]+4x+[9+5]. The expression that can be used to find the sum of the polynomials given above is [(-3x^2)+(-8x^2)]+4x+[9+5].