You don't. There is no way to factorise it.
x3 - 9x = x(x2 - 9) = x(x2 - 32) = x(x - 3)(x + 3)
x3 + 4x2 + 16x + 64 =x2*(x + 4) + 16(x + 4) = (x + 4)*(x2 + 16) which has no further real factors.
√(16x) = 4√x = 4x1/2
If your function is 4x^2+16x+16=0 then x=-2, if it is 4x^2-16x+16=0, then x=2
16x^3 - 9x x (16x^2 - 9) x (4x +3 ) (4x - 3)
2 * 2 * 2 * 2 * x * x * x = 16x^3
Too bad that's not x^2 - 16x + 64 which factors to (x - 8)(x - 8)
64 x cubed minus y cubed is (4x - y)(16x^2 + 4xy + y^2)
x3 + 4x2 - 16x - 64 = (x + 4)(x + 4)(x - 4).
X3 + 8= (x+2)(x2-2x+4)
6x^3 + 3x = 3x(2x^2 + 1)
It depends on what you wanted to do - graph it, solve it, factorise it, etc.
You don't. There is no way to factorise it.
To factorise x3 + 5x2 - 16x - 80 I note that -80 = 5 x -16 and 5 & -16 are the coefficients of x2 and x. Thus I have: x3 + 5x2 - 16x - 80 = (x + 5)(x2 - 16) and the second term is a difference of 2 squares, meaning I have: x3 + 5x2 - 16x - 80 = (x + 5)(x + 4)(x - 4)
[(-16x)12]1/3 = (-16x)4 = 65536x4
x3 - 9x = x(x2 - 9) = x(x2 - 32) = x(x - 3)(x + 3)