Question

Which of the following is (-5x + 4) – (3x^2- 7x + 4) simplified and written in standard form?A. 3x^2 - 12x + 8B. 2x - 3x^2C. -3x^2 + 7x - 5xD. -3x^2 + 2x

Answer 1

Answer: D

Explanation:

The expression we have is:

$(-5x+4)-(3x^2-7x+4)$

First we use the distributive property to multiply the "-" by the second parenthesis, also we can ignore the parenthesis on the first term:

$-5x+4-3x^2+7x-4$

This is because "-" by 3x^2 is equal to -3x^2. And "-" by -7x is equal to +7x, and "-" by +4 is equal to -4.

Next, we combine like terms (terms that have the same variable are like terms, also independent terms without variable are like terms):

$2x-3x^2$

This is because -5x+7x =2x, and +4-4=0 so they are eliminated.

To present this in standard form we leave the term with the bigger exponent at the beginning of the expression:

$-3x^2+2x$

Which is option D.