Question

How do you factor the expression `27x^3 + 343y^3`?

Answer 1

`=(3x+7y)(9x^2-21xy+49y^2)`

Explanation:

`27x^3+343y^3`
`=(3x)^3+(7y)^3`
Using the formula
`a^3+b^3=(a+b)(a^2-ab+b^2)`
the given expression becomes
`=(3x+7y)(3x)^2-3x*7y+(7y)^2`
`=(3x+7y)(9x^2-21xy+49y^2)`