Posted by Jane on Friday, January 1, 2010 at 5:53am.
Learn and apply the FOIL method.
(First, Outside, Inside, Last)
That describes the pairs of terms that you must multiply and then add together.
http://www.algebrahelp.com/lessons/simplifying/foilmethod/pg2.htm
To learn algebra, you really need the practice doing this yourself
surely, it would be x^3-2x-15
please correct me if i'm wrong
Chelsea is wrong. Only the -15 term is correct. There is no cubic (x^3) term
i looked at the site, now i'm really confused, could you just show me the answer and working out, we haven't done the foil method in school we do it differently.
What you are doing in school must be the same thing, perhaps with a different name.
Why do you keep changing your name?
When you multiply the first pair you get
2x * x = 2x^2
That is the first term.
When you multiply the "inside" pair you get -5x
Now you do the others and combine terms.
The answer you should get is
2x^2 +x -15