Question 16559
First take out the common factor which is x:
{{{2x^3-x^2-15x}}}


{{{x(2x^2 - x -15)}}}


Next, try to factor the trinomial into the product of two binomials, beginning with the {{{2x^2}}}.  The only way to break this down is to say 2x *x.  The signs will be opposite, since the last term is a -15.


{{{x(2x+ _____)*(x-_____)}}}


Next, you need to find a combination of -15, what times what will come out to -15 in such a way that the outer times outer terms will subtract and give you a -1x for the middle term.  The combination that works is 5 times -3, as follows:


{{{x(2x+5)*(x-3) }}}, where the outer times outer is -6x and the inner times inner is +5x, for a total of -1x.  That should do it:


{{{x(2x+5)*(x-3) }}}


R^2 at SCC