Question

How do you factor completely `8w^3 - 4w^2 - 60w`?

Answer 1

`4w(2w+5)(w-3)`

Explanation:

Always look for a common factor first. In this case it is `4w`

`8w^3 - 4w^2 - 60w = 4w(2w^2 -w -15)`

Now, find factors of 2 and 15 which subtract to give 1.
There must be more negatives.

find the cross products and subtract.
`" 2 5 "rArr 1xx5 = 5`
`" 1 3 "rArr2 xx3 = 6" 6-5 = 1"`

But we need `-1," 6 must be negative and 5 must be positive"`

=`4w(2w+5)(w-3)`