Question

How do we get from

-1/32 = r^3
to
r = -1/2

I guess what I'm really asking is how to simplify exponents, if that makes sense?

Answer 1

It's not correct.

We can verify this by noticing that...

r = -1/2

r^3 = (-1/2)^3

r^3 = (-1/2)*(-1/2)*(-1/2)

r^3 = ( -1*(-1)*(-1) )/(2*2*2)

r^3 = -1/8

So if you change the 32 to 8 in the original equation, then it would solve to r = -1/2

Your teacher made a typo somewhere.