Question

How do you expand `(x^4-y^3)^3`?

Answer 1

`x^12-3x^8y^3+3x^4y^6-y^9`

Explanation:

Since

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

you have:

`(x^4-y^3)^3=(x^4)^3+3(x^4)^2(-y^3)+3(x^4)(-y^3)^2+(-y^3)^3`

that's

`x^12-3x^8y^3+3x^4y^6-y^9`