if its a normal Algebraic multiplication then it will be simply like this -
i am writing it in words.....(square,cube)
(x+3) (2x^2-4x-7) is
= x (4x(square) -4x -7) +3 (4x(square) -4x -7)
= 4x(cube) -4x(square) -7x +12x(square) -12x -21
=4x(cube) +8x(square) --5x -21
hope this is what is needed ......
