Question

How do you factor `125x^3 + 216`?

Answer 1

`125x^3=5x` and `216=6^3`

We can use the sum of cubes to factor `(125x^3+216)`.

`(a^3+b^3)=(a+b)(a^2-ab+b^2)`

`a=5x`
`b=6`

`(5x+6)((5x)^2-(5x)(6)+6^2)`=

`(5x+6)(25x^2-30x+36)`