The trick here is to recognize one or more factors common to each term. For example, 6x4 − 24x3 + 72x2 = x^2(6x^2 - 24x + 72), so x^2 is one common factor. Looking at (6x^2 - 24x + 72), you can easily see that 6 is a common factor, so now we have (6)(x^2)(x^2 - 4x + 12). These last 3 terms do not have a common factor, so the factoring process stops here:
(6)(x^2)(x^2 - 4x + 12)
