does -(-6x(2x)) equal -12

No, -(-6x(2x)) does not equal -12.

To simplify the expression, we need to apply the distributive property first:
-(-6x(2x)) = (-1)(-6x)(2x)

Then multiply:
(-1)(-6x)(2x) = 12x^2

So, -(-6x(2x)) simplifies to 12x^2, not -12.