I know how to expand when the expression is like: $a^2-b\qquad\text{ which expands to }\qquad(a+b^{1/2})(a-b^{1/2})$ or like $a^4-b\qquad\text{ which expands to }\qquad(a^2+b^{1/2})(a^2-b^{1/2})$
But what is the method / formula to expand expressions like:
$a^3-b$
I would assume its something like the product of a quadratic and a binomial but I am not sure how to get there.