Hello Paula,

Use these rules of exponent to solve this problem.

1.   a^m/aⁿ = a^m-n

2.   a^-1 = 1/a

3.   a^m * aⁿ = a^m+n

4x^-2y³/x⁵y^-6             (original problem)

4 * (y³y⁶/x⁵x²)         (x^-2 = 1/x² and 1/y^-6 = y⁶)

4 * (y³⁺⁶/x⁵⁺²)

4y⁹/x⁷    ---------------->answer

Hope this helps.