Well when you see parentheses set up like these together that automatically means to multiply. The solution is: <span>Apply the FOIL method: <span>(a+b)(c+d)=ac+ad+bc+bd</span> </span><span><span>x2</span>+5x+3x+15</span> <span>Simplify </span><span><span><span>x2</span>+8x+15</span></span>