Question 799618
Two choices:
Distributive Property, or Long-Hand Multiplication as the terms cross.


Guess which method I am using here:


____________{{{x^2}}}_____{{{2x}}}_____{{{4}}}
_______________________________
_____{{{x}}}______{{{x^3}}}_____{{{2x^2}}}___{{{4x}}}
_____
_____{{{3}}}_____{{{3x^2}}}_____{{{6x}}}_____{{{12}}}
_____



The leftmost column shows the terms of the first polynomial factor.  The topmost row shows the terms of the second polynomial factor.  The rest of the terms are to be summed; and they are the product of each corresponding row and column; and then you combine like terms to simplify.