Notes on 9.3 factoring trinomials (part 1)

*FInd 2 factors of the constant term that add to the middle term.

*You put the problem in decreasing order.

ex) x^2+5x+6 6

1,6

2,3...2+3= 5 and 2(3)=6

Answer: (x+2)(x+3)

WHEN NEGATIVE...

ex) x^2-7x-30 30

1,30
2,15

3,10...you must change 10 to -10 and keep 3 as +3. 3-10=-7 and 3(10)=30

5,6
Answer: (x-10)(x+3)

WHEN NEGATIVE AND POSITIVE...

ex) x^2-13x+40 40

1,40
2,20
4,10

5,8...except this time both 5 and 8 and negative making a sum of -13.

Answer: (x-5)(x-8)