Question

The expression below is the factorization of what trinomial? (4x + 5)(9x + 9) A. 13x2 + 81x + 45 B. 13x2 + 14x + 45 C. 36x2 + 14x + 45 D. 36x2 + 81x + 45

Answer 1

Use the FOIL method to find the trinomial.

FOIL - First, Outer, Inner, Last

(Bolded terms are the terms being multiplied.)

First
(4x + 5)(9x + 9)

$4x * 9x = 36x^{2}$

Outer
(4x + 5)(9x + 9)

$4x * 9 = 36x$

Inner
(4x + 5)(9x + 9)

$5 * 9x = 45x$

Last
(4x + 5)(9x + 9)

$5 * 9 = 45$

Add all of these results together:

$36x^{2} + 36x + 45x + 45$

Simplify by combining like terms.

$36x^{2} + 81x + 45$

The answer is D. 36x^2 + 81x + 45.