# How do you factor completely #18x^4+9x^3-20x^2#?

##### 1 Answer

#### Explanation:

Let's start with the original:

We can first factor out

From here, we need to find factors for the terms within the brackets in the form of

and there's some trial and error to this.

Let's play with

We have a different story with

So let's see if we can find a combo that works:

For a=6, b=-4, c=3, d=5; ac = 18, bd = -20, ad+bc = 30-12=18

For a=6, b=-5, c=3, d=4; ac = 18, bd=-20, ad+bc = 24-15=9

Ok - found a combo that works. Let's factor: