Question

r^3 + r^2 = r^2 - 64

Answer 1

We have the following equation

$r^3+r^2=r^2-64$

and we want to find r.

We can note that the term r squared is in both sides, then we can cancel r^2 out and get

$r^3=64$

By applying cubic root in both sides, we have

$r=\sqrt[3]{64}$

then, the answer is

$r=4$