Question

How do you find the gcf of `20x^2 - 18xy`?

Answer 1

The two terms of `20x^2-18xy` have a gcf of `2x`

Explanation:

Prime factors of:
`20x^2` are `[color(red)(2),2,5,color(red)(x),x]`
`18xy` are `[color(red)(2),3,3,color(red)(x), y]`

The factors common to both prime factor decomposition are:
`color(white)("XXXX")` `[2,x]`
and the greatest common factor (gcf) is
`color(white)("XXXX")` `2 xx x = 2x`