here's an example Its also call the 'ac' method:-
factor 2x^2 - 13x - 15
Multiply first coefficient by last number which is 2*-15 = -30
Now we need 2 factors of -30 which will when added give - 13:-
-15 and 2 looks good. So we can write:-
2x^2 - 13 x - 15
= 2x^2 + 2x - 15x - 15
factor by grouping first 2 and last 2 terms , we get:-
= 2x(x + 1) - 15(x + 1)
the x+1 is common so we have:-
(2x - 15)(x + 1) Answer
Hope this helps.
