So what we're going to do here is FOIL (first, inner, outer, last):
[tex](6 a^{3}*4 a^{2})+ (6 a^{3}*5 b^{2})+(-3 b^{3}* 4 a^{2})+(-3 b^{3}*5 b^{2})[/tex]
When we multiply exponents, and they have the same base (for example both have a or both have b), we add them. Let's simplify this expression:
[tex]24 a^{5} +30 a^{3} b^{2}+(-12 b^{3} a^{2})+(-15 b^{5}) [/tex]
Which can be further simplified to:
[tex]24 a^{5} +30 a^{3} b^{2}-12 b^{3} a^{2}-15 b^{5} [/tex]
