Question

Factor completely: 5x^2 - 40

would it be 5(x + 8)(x - 8)?

Answer 1

Right :)

Answer 2

You use first Common monomial then Factor the remaining terms

Answer 3

It would be 5(x + 2)(x - 2)

Answer 4

Whenever you have something like \( a^{2} -b^{2}\) then you can factor it like \( (a+b)(a-b)\) since you have \(5x^{2}-40\) we can rewrite as \(5(x^2-8)\). This is now in the form we can use the technique I just described.:

\(5(x^{2}-\sqrt{8}^{2})=5(x+\sqrt{8})(x-\sqrt{8})=5(x+2\sqrt{8})(x-2\sqrt{8})\).