#(color(red)(a*a)(a+b)*color(red)(ab)(a^2+b+color(blue)(a+a))#
#=color(red)(a^3b)(a+b)(a^2+b+color(blue)(2a))#
#=a^3b(color(magenta)(a)color(forestgreen)(+b))(a^2+2a+b)" "larr# multiply the two brackets
#=a^3b(color(magenta)(a^3+2a^2+ab)+color(forestgreen)(a^2b+2ab+b^2))#
#=a^3b(a^3+2a^2+a^2b+3ab+b^2)" "larr# distribute the #a^3b#
#=a^6b +2a^5b+a^5b^2+3a^4b^2+a^3b^3#