Algebra 2: Section 5.2
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Transcript of Algebra 2: Section 5.2
1
Algebra 2: Section 5.2
Solving Quadratic Functions by Factoring
2
Factoring Quadratic Expressions
Factoring a Trinomial of the Form
When factoring ask yourself,
what two numbers multiply
together to be ‘c’ and add together
to be ‘b’.
2x bx c
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21. 2 48x x
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Factoring Quadratic Expressions
Factoring a Trinomial of the Form
First, look for common factor!
Trial and Error– Write down factors of a and c
– Try combinations until the correct factorization
is found
2ax bx c
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22. 4y 4 3y
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23. 10 19 7x x
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24. 5 17 14x x
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Factoring Quadratic Expressions
Difference of Two Squares
2 2 ( )( )a b a b a b
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25. 49x 26. 16 225y
( 7)( 7)x x (4 15)(4 15)y y
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Factoring Quadratic Expressions
Perfect Square Trinomial
2 2 2
2 2 2
2 ( )
2 ( )
a ab b a b
a ab b a b
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27. 4 12 9z z 28. 36 60 25w w
2 2(2 ) 12 (3)z z
2 2(2 ) 2(2 )(3) (3)z z
2(2 3)z
2 2(6 ) 60 (5)w w
2 2(6 ) 2(6 )(5) (5)w w
2(6 5)w
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General Steps for Factoring
Quadratic Expressions
1) If necessary, factor out any
common factor
2) Factor the new expression into
two binomials (if possible)
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29. 14 2 12x x210. 3 18y y
211. 4 36x 212. 12 3 3x x
22(7 6)x x
2(7 6)( 1)x x
3 ( 6)y y
24( 9)x
4( 3)( 3)x x
23(4 1)x x
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Solving Quadratic Equations
Zero Product Property
–If AB = 0, then A = 0 or B = 0
If ( 3)( 2) 0, thenx x
3 0 or 2 0x x
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Solving Quadratic Equations
General Steps to Solve
–If necessary, move all terms to the
one side (leave zero on the other)
–If necessary, combine like terms
–Factor
–Solve using the Zero Product
Property
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213. 9 12 4 0t t 214. 3 -6 10x x
2 2(3 ) 2(3 )( 2) ( 2) 0t t
2(3 2) 0t
3 2 0t
3 2t
2
3t
20 3 4x x
0 ( 4)( 1)x x
4 0 or 1 0x x
4 or 1x x
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Finding Zeros of Quadratic
Functions
Zeros of a function
–The x-values at which the graph
crosses the x-axis
–when y = 0
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215. 3 14 5y x x 216. 8 15y x x
20 3 14 5x x
0 (3 1)( 5)x x
3 1 0 or 5 0x x
3 1 or 5x x
1 or 5
3x x
20 8 15x x
0 ( 5)( 3)x x
5 0 or 3 0x x
5 or 3x x
Assignment
p.260
#23-87 odds, 92
(34 problems)
19
Assignment
p.260
#24-88 evens, 94
(34 problems)
Math Journal
Factoring with Algebra Tiles
p.262 #96 (parts a and b)20