Answer:
4x²+17x-15
Use the FOIL method. Multiply the first term in each group, then the outer ones, then the inner ones, and finally the last term in each group together. The first terms in this case are 4x and x, the outer terms are 4x and 5, the inner terms are -3 and x, and the last terms are -3 and 5.
Hope this helps!