RCSD Geometry Local MATHEMATICS CURRICULUM
Name:___________________________________
Lesson 7
U5
Period:________ Date:__________GEOMETRY
Lesson 7 Factoring Trinomials with a Leading Coefficient greater than 1
Learning Target: I can factor trinomials with a leading coefficient
Opening Exercise. Multiply the binomials:
(2𝑥 + 3)(𝑥 + 5)
Example 1. Factor the trinomial: 2𝑥 2 + 13𝑥 + 15
Example 2: Factor
3𝑥 2 − 2𝑥 − 5
Example 3:
Factor 3𝑥 2 − 𝑥 − 4
Example 4:
Factor 𝟐𝒙𝟐 − 𝟔𝒙 − 𝟖
RCSD Geometry Local MATHEMATICS CURRICULUM
Name:___________________________________
Example 5. Factor the trinomial: 8𝑥 2 − 10𝑥 − 3
1) Identify the a,b and c terms: a = , b =
c=
2) Multiply the a to the c term:
3) List the factors of ac:
4) Fill in the terms on the table
5) Factor the GCF out of each group
6) (_____________)(___________)
Example 6: Factor 6𝑥 2 – 7𝑥– 3
1) Identify the a,b and c terms: a = , b =
c=
2) Multiply the a to the c term:
3) List the factors of ac:
4) Fill in the terms on the table
5) Factor the GCF out of each group
6) (_____________)(___________)
Example 7. 6𝑥 2 + 19𝑥 + 10
****Remember to follow instructions on how to use your
calculator to help find those factors of ac that add to b.
a. Go to the Y = screen
b. Y1 = type (A*C)/x
c. Y2 = Y1 + x ** (To put Y1 on your screen go to VARS
>YVARS ENTER ENTER)
d. Go to the TABLE screen ** 2nd GRAPH
e. Locate in the Y2 column 19
f. Then in the X and Y1 are the 4 and 15
Lesson 7
U5
Period:________ Date:__________GEOMETRY
RCSD Geometry Local MATHEMATICS CURRICULUM
Name:___________________________________
Lesson 7
Period:________ Date:__________GEOMETRY
Now you try on your own
Factor each trinomial
9.
10x2 + 9x + 2
10. 11x2 - 10x – 1
11.
2x2 - x - 10
12. 4𝑥 2 − 19𝑥 + 12
13. 8𝑥 2 − 5𝑥 − 3
14.
2𝑥 2 − 21𝑥 − 36
[This might be a challenge]
15.
8.
16.
3x2 + 11x – 4
U5
2𝑥 2 − 3𝑥 − 9
4𝑥 2 − 12𝑥 + 9 [This one is tricky, but look for a special pattern.]
RCSD Geometry Local MATHEMATICS CURRICULUM
Name:___________________________________
Lesson 7
U5
Period:________ Date:__________GEOMETRY
Lesson 7 Factoring Trinomials with a Leading Coefficient greater than 1
Problem Set
Factor the expanded form of these quadratic expressions. Pay particular attention to the +/- signs.
1.
3𝑥 2 − 2𝑥 − 8
2. 3𝑥 2 + 10𝑥 − 8
3. 3𝑥 2 − 13𝑥 + 12
4. 5𝑥 2 + 19𝑥 − 4
5. 5𝑥 2 − 2𝑥 − 7
6. 6𝑦 2 − 5𝑦 + 1
7. 8𝑥 2 + 65𝑥 + 8
8. 2𝑥 2 − 5𝑥 − 12
RCSD Geometry Local MATHEMATICS CURRICULUM
Name:___________________________________
Lesson 7
U5
9. 2𝑥 − 𝑥 − 15
Period:________ Date:__________GEOMETRY
10. 6𝑥 2 + 𝑥 − 12
11. 7𝑥 2 − 11𝑥 – 6
12. 2𝑥 2 + 9𝑥 + 4
13. −10𝑥 2 − 17𝑥 + 6
14. – 2𝑥 2 + 5𝑥 − 2
2