# How do you factor #y= 3x^7 - 9x ^6 + 18x ^5#?

##### 1 Answer

Dec 16, 2015

#y = 3x^7-9x^6+18x^5=3x^5(x^2-3x+6)#

#### Explanation:

First note that all the terms are divisible by

#y = 3x^7-9x^6+18x^5=3x^5(x^2-3x+6)#

The remaining quadratic factor is in the form

This has discriminant

#Delta = b^2-4ac = (-3)^2-(4xx1xx6) = 9-24 = -15#

Since this is negative, the quadratic has only Complex zeros and cannot be factored any further with Real coefficients.