In order to factor this, you need to look at the coefficient
of the last term which is -12. After that, you need to think of two factors of
this number that would yield to -1 (which is the coefficient of the second
term) when added or subtracted. You will get -4 and 3 (-4 + 3 = -1). Therefore,
the expression would become (a – 4b)(a + 3b). This expression is the complete
factors of the expression given.
Note: This is applicable when the coefficient of the first
term is 1.
