Factor by grouping.
-$$x ^ { 3 } - x ^ { 2 } + 9 x - 9$$
A) $\left( x ^ { 2 } - 9 \right) ( x + 1 )$
B) $\left( x ^ { 2 } + 9 \right) ( x - 1 )$
C) $\left( x ^ { 2 } - 1 \right) ( x + 9 )$
D) $\left( x ^ { 2 } + 1 \right) ( x - 9 )$

Question

Quizplus · Accepted Answer

To factor by grouping, we first split the expression into two groups: $x^3 - x^2$ and $+9x - 9$. Factoring out the greatest common factor from each group gives us $x^2(x - 1) + 9(x - 1)$. Factoring out the common factor $(x - 1)$ from both terms gives us $(x^2 + 9)(x - 1)$, which matches choice B.

Factor by Grouping x3−x2+9x−9x ^ { 3 } - x ^ { 2 } + 9 x - 9x3−x2+9x−9

Factor by Grouping $x ^ { 3 } - x ^ { 2 } + 9 x - 9$