Factor the sum or difference of cubes.
-$125 r ^ { 3 } + 8$
A) $( 5 r + 2 ) \left( 25 r ^ { 2 } - 10 r + 4 \right)$
B) $( 5 r + 2 ) ^ { 2 } ( 5 r - 2 )$
C) $( 5 r + 2 ) \left( 25 r ^ { 2 } - 20 r + 4 \right)$
D) $( 5 r - 2 ) \left( 25 r ^ { 2 } + 10 r + 4 \right)$

Question

Quizplus · Accepted Answer

The sum of cubes can be factored using the formula $a^3 + b^3 = (a + b)(a^2 - ab + b^2)$. Here, $125r^3 = (5r)^3$ and $8 = 2^3$, so applying the formula gives $(5r + 2)(25r^2 - 10r + 4)$.

Factor the Sum or Difference of Cubes 125r3+8125 r ^ { 3 } + 8125r3+8

Factor the Sum or Difference of Cubes $125 r ^ { 3 } + 8$