Abc plus 4cba plus 2cab-11bca plus 3acb equals?
abc + 4cba + 2cab - 11bca + 3acb = ?
First off, because each term created through multiplication, the
order of the variables does not matter, so the first step is to
rewrite the each term with the same order of the variable, to see
if they all have the same ones
abc + 4abc + 2abc - 11abc + 3abc = ?
they all do have the same variables, so you can now just
add/subtract the leading numbers going from left to right
5abc + 2abc - 11abc + 3abc = ?
7abc - 11abc + 3abc = ?
-4abc + 3abc = ?
-abc