GRE Quantitative Reasoning Practice Exam

Raising a fraction to a power applies the exponent to both the top and the bottom. So (x/y) cubed is x^3 over y^3. You can see this by multiplying the fraction by itself three times: (x/y) * (x/y) * (x/y) = (x*x*x)/(y*y*y) = x^3/y^3. Just remember this is defined when the denominator isn’t zero, so y ≠ 0.

If you see alternatives like x^3 y^3, that would come from treating (xy)^3, not (x/y)^3. If you see x^3/y, that would be applying the exponent only to the numerator, and x y^3 would apply the exponent only to the y in the denominator or mis-handle the division. The correct expression is x^3/y^3.