Answer:
4x(x-10)(x+10)
Step-by-step explanation:
4x^3-400x
Factor out 4x
4x(x^2-100)
We know that x^2-100 is the difference of squares
a^2 - b^2 = (a-b)(a+b)
4x(x^2-100)= 4x(x^2 -10^2)
