| WHAT TO DO:
|
HOW TO DO IT: |
| Given general trinomial of type
that has no common factor.
[Read ± as + or − ]
Read the “clues of the signsâ€.
|
 |
| Find product of first and last coefficients.
This is the grouping number (GN)
|
GN
A·C = P |
| Find all possible factors of GN = P
whose sum or difference is B
(depending on the sign before C.)
+ sum
or
− difference |
P = r·s , r > s
(r + s) = B
(r − s) = B |
| 1) + sum both factors get middle sign
2) − difference largest factor gets middle sign |
|
| Regroup: into 4 terms, with the proper signs
then factor by grouping.
|
Ax2 ± rx ± sx ± C
(ax ± b)(cx ± d) |
| Try the following example before you turn the page: |
|
| Example: 6x2 + 23x + 20 |
6x2 + 23x + 20 |