If a trinomial ax
1. Set up empty parentheses:
If a,b,c are positive, then both signs are positive
If b is negative but c is positive, then both signs arenegative .
If c is negative, then one sign is positive and the other isnegative .
2. Try the factors of a in front positions
Example: factor 2x
step 3: The factors of 2 are 2 and 1; the factors of 10 are 10and 1 or 5 and 2:
(2x + 10)(x - 1) = 2x
(2x + 5)(x - 2) = 2x
The second trial is almost correct; only the sign of themiddle term is wrong. So we change signs:
(2x - 5)(x + 2) = 2x
The answer is (2x - 5)(x + 2) .