Ok, sqrt(-32) deals with imaginary numbers. This is because you can't take the square root of a negative number. So, we'll split that up into:
sqrt(32)•sqrt(-1)
And since sqrt(-1) = i, I'll use that from this point forth.
So we have i•sqrt(32)
Now, to simplify sqrt(32), we'll split it up into sqrt(16) • sqrt(2) because sqrt(16) =4
This will leave us with a final answer of 4isqrt(2)
Hope this helps & wasn't too confusing!
