Step-1 : Multiply the coefficient of the first term by the constant 4 • -10 = -40
Step-2 : Find two factors of -40 whose sum equals the coefficient of the middle term, which is 7 .
|
-40 |
+ |
1 |
= |
-39 |
|
|
-20 |
+ |
2 |
= |
-18 |
|
|
-10 |
+ |
4 |
= |
-6 |
|
|
-8 |
+ |
5 |
= |
-3 |
|
|
-5 |
+ |
8 |
= |
3 |
|
|
-4 |
+ |
10 |
= |
6 |
|
|
-2 |
+ |
20 |
= |
18 |
|
|
-1 |
+ |
40 |
= |
39 |
|
Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored
Final result :
5 • (4x
2 + 7x - 10)