Question

How do you factor `9x^3-36x`?

Answer 1

`9x(x-2)(x+2)`

Explanation:

`"take out a "color(blue)"common factor "9x`

`=9x(x^2-4)`

`x^2-4larr"is a "color(blue)"difference of squares"`

`•color(white)(x)a^2-b^2=(a-b)(a+b)`

`rArrx^2-4=(x-2)(x+2)`

`rArr9x^3-36x=9x(x-2)(x+2)`