Question

What is the product of the polynomials below?
(5x2 + 5x + 7)(8x + 6)

A. 48x3 + 70x2 + 86x + 42
B. 40x3 + 60x2 + 86x + 42
C. 40x3 + 70x2 + 86x + 42
D. 40x3 + 10x2 + 86x – 42

Answer 1

Hi there! The answer is C.

$(5 {x}^{2} + 5x + 7)(8x + 6) = \\ work \: out \: parenthesis \\ \\ 40 {x}^{3} + 30 {x}^{2} + 40 {x}^{2} + 30x + 56x + 42 = \\ collect \: terms \\ \\ 40 {x}^{3} + 70 {x}^{2} + 86x + 42$

Answer 2

The answer is C

40x3 + 70x2 + 86x + 42