Take into account that the volume of a cube is given by:
V = a³
where a is the side of the cube. In this case a = 4y⁴ feet. Replace this value of a into the previous expression for V:
V = (4y⁴ ft)³ = 4³y¹² ft³ = 64y¹² ft³
where you have used properties of exponents.
ence, the volume of the box with a shape of a cube is 64y¹² ft³