Factor by grouping.
-$$x ^ { 3 } + 2 x ^ { 2 } - 10 x - 20$$
A) $\left( x ^ { 2 } + 2 \right) ( x - 10 )$
B) $( x + 2 ) \left( x ^ { 2 } - 10 \right)$
C) $( x + 2 ) \left( x ^ { 3 } - 10 x \right)$
D) $( x - 2 ) \left( x ^ { 2 } - 10 \right)$

Question

Quizplus · Accepted Answer

We can group the first two terms and the last two terms as follows:
$$(x^3+2x^2) - (10x+20)$$
Now we factor out the common terms from each group,
$$x^2(x+2)-10(x+2)$$
Now we can see that we have the common factor of $(x+2)$ in both terms. So we can factor it out,
$$(x+2)(x^2-10)$$
So the final answer is $\boxed{\textbf{(B) }(x+2)(x^2-10)}$.

Factor by Grouping x3+2x2−10x−20x ^ { 3 } + 2 x ^ { 2 } - 10 x - 20x3+2x2−10x−20

Factor by Grouping $x ^ { 3 } + 2 x ^ { 2 } - 10 x - 20$