How to solve it
WyzAnt Tutors: Sign In to answer this question.
Are you trying to expand this? If so, FOIL it. First, Outside, Inside, Last.
FIRST - x^2
OUTSIDE - -15
INSIDE - -3x
LAST - 5x
Add them all up - x^2 -3x+5x-15, and then simplify to x^2+2x-15.