Please show me how to simplify these expressions:1) (-x)^2(-x)^5

Question

2) (-3m^3)^2

3) (x/y)^-3

Thanks very much for your consideration.

Answer 1

(-x)^2 (-x)^5 = (-x)^7 = -x^7

(-3m^3)^2 = (-3)^2 (m^3)^2 = 9m^6

(x/y)^-3 = (y/x)^3 = y^3/x^3
or,
(x/y)^-3 = x^-3 / y^-3 = x^-3 y^3