Factor.
-$5 r^{3}-135 s^{3}$
A) $5(r-3 s)\left(r^{2}+3 r s+9 s^{2}\right)$
B) $(5 r-3 s)\left(r^{2}+15 r s+45 s^{2}\right)$
C) $5(r+3 s)\left(r^{2}-3 r s+9 s^{2}\right)$
D) $5(\mathrm{r}-3 \mathrm{~s})\left(\mathrm{r}^{2}+9 \mathrm{~s}^{2}\right)$

Question

Quizplus · Accepted Answer

The expression $5 r^{3}-135 s^{3}$ can be factored as a difference of cubes, $a^3 - b^3 = (a - b)(a^2 + ab + b^2)$, where $a = r$ and $b = 3s$. This gives $5(r-3 s)\left(r^{2}+3 r s+9 s^{2}\right)$.

Factor - 5r3−135s35 r^{3}-135 s^{3}5r3−135s3 A) 5(r−3s)(r2+3rs+9s2)5(r-3 s)\left(r^{2}+3 r s+9 s^{2}\right)5(r−3s)(r2+3rs+9s2) B) (5r−3s)(r2+15rs+45s2)(5 r-3 s)\left(r^{2}+15 r s+45 s^{2}\right)(5r−3s)(r2+15rs+45s2)

Factor
- $5 r^{3}-135 s^{3}$ A) $5(r-3 s)\left(r^{2}+3 r s+9 s^{2}\right)$ B) $(5 r-3 s)\left(r^{2}+15 r s+45 s^{2}\right)$