Question

can someone explain how -2y is the cube root of -8y^3

Answer 1

Take note that 2^3 = 2*2*2 = 8


So (-2)^3 = (-2)*(-2)*(-2) = -8


Also, y^3 = y*y*y = y^3


So (-2y)^3 = (-2y)*(-2y)*(-2y) = -8y^3


The cube root simply "undoes" the cubing.

Answer 2

-2y times three = 8y^3

(-2y)*(-2y)*(-2y) = (4y^2)*(-2y) = -8y^3