Which expression is equivalent to (9x2 + 2x – 7)(x – 4)? a. x(9x2 + 2x – 7) + 4(9x2 + 2x – 7) b. (9x2 + 2x – 7)(x) + (9x2 + 2x – 7)(–4) c. x(9x2 + 2x – 7) – 4 d. –4x(9x2 + 2x – 7)

B.

Step-by-step explanation:

Given two expressions between parentheses that are multiplying between them, we can find the equivalent expression if we distribute the terms between them. For example :

The expression is equivalent to

because we multiply the first element of the first expression (a+b) by the first element of the second expression (c+d) and then we sum the product between the first element of the expression (a+b) and the second element of the second expression (c+d).Then, we sum the product of the second element of the expression (a+b) and the first element of (c+d) and finally we sum the product of the second element of (a+b) and the second element of (c+d) in order to find the equivalent expression of (a+b).(c+d).

In the exercise :

Rearranging the expression we obtain :

Factoring the expression :

The correct answer is B.