Factoring questions

[marcuk]

Hi,

Still working on my homework, and I am at a complete loss over factoring, is there a certain way to tell which is the best way to factor an equation? a,b,c method or another way?

example of problem:

yw-9w+zy-9z

Thanks,
Kim

 

[pka]

\(\displaystyle yw-9w+zy-9z=w(y-9)+z(y-9)\)

 

[Loren]

Only experience will help. You still need to follow a couple of basic procedures. Always look for a common monomial factor first. Then, if you have a binomial, look for the difference of perfect squares. If you have a polynomial of three terms you can try FOIL or another method to factor a trinomial. If you have a polynomial of four terms, your best bet, usually, is to try grouping.

yw-9w+zy-9z

Group this into (yw-9w)+(zy-9z).
Now, factor out any common monomial factors and go from there.