Download 2.7 Factor ax2 + bx + c **now we have a number in front of x2

Questions over 2.6 HW??
Warm-Up
1.
Factor each trinomial:
x2 + 10x + 16
2.
y2 + 2y – 63
3.
z2 – 5z – 24

2.7
2
Factor ax + bx + c
(now we have a number in front of x2)
2.6-2.7 Quiz: Friday
2.6-2.9 Test: 2/26/10
Goal:

Factor trinomials of the form ax2 + bx + c
Now we have an extra
number to work with
Example 1:

Factor: 5n2 – 12n + 7

Solution
5n2 – 12n + 7
Multiply the first and
last numbers
35
Now, what two numbers will add to give you
-12 and multiply to give you 35?
-5 and -7
Bring down 5n to both factors: (5n
)(5n
)
(5n – 5)(5n – 7)
**Now think…do either of your factors have anything in
common???
(5n – 5) have a 5 in common
Cont’d:
(5n – 5) have 5 in common, so we can
divide by 5
5
5
(n – 1)
So our answer is:
(5n – 5)(5n – 7)  (n – 1)(5n – 7)
You Try:

Factor 7a2 – 50a + 7

Solution:
7a2 – 50a + 7
(7a – 1)(7a – 49)
(7a – 1)(a – 7)
Example 2:

Factor 3m2 – 5m – 22

Solution
3m2 – 5m – 22
-66
(3m + 6)(3m – 11)
(m + 2)(3m – 11)
You Try:

Factor 4b2 – 8b – 5

Factor 6c2 + 5c – 14
Example 3:

Factor -2x2 + 11x – 12

Solution
-2x2 + 11x – 12
we want to get rid of the negative
-(2x2 – 11x + 12)
24
-(2x – 8)(2x – 3)
-(x – 4)(2x – 3)
You Try:

Factor -3r2 – 7r – 4

Factor -12y2 + 5y + 2
Last one 

Factor: 10n2 – 26n + 12
Homework:

P. 87 #1-23odd