|WHAT TO DO:
HOW TO DO IT:
|Given a trinomial of type ax2 + bx + c that has
no common factor, where signs may be positive or
negative. Separate the signs from the coefficients.
[Read Â± as + or - ]
Read the â€œclues of the signsâ€.
|Find product of first and last coefficients.
This is the grouping number (GN)
AÂ·C = P
|Find all possible factors of GN = P
whose sum or difference is B
(depending on the sign before C.)
|P = rÂ·s
, r > s
(r + s) = B
(r - s) = B
Given: 10x2 + 11x - 6
10Â·6 = 60
|The last sign is â€œ−â€ so find the pair of factors
of 60 that has a difference of 11.
|The largest factor of the pair gets middle sign, +
||+ 15 and
|The trinomial can be arranged in four terms using
these values as coefficients of x, grouped 2 Ã— 2
+ 15x − 4x − 6
|Factor common factor from each group:
5x(2x + 3) − 2(2x + 3)
|Find common term in ( ), factor:
||(5x − 2)(2x + 3)
|Check by FOIL method.