It is nonequivalent. Figure it out this way. Think about what number has to be multiplied by both the numerator and the denominator of to get to
. It has to be the samee number for the one expression to be equivalent to the other. To get from 5x to x^3, we have to multiply by 1/5x^2. When we do that we get x^3. Good. Now we have to multiply the denominator by the same thing, 1/5x^2.
. As you can see, they are not equivalent.