U2C5.notebook
September 16, 2014
Solving Quadratic Equations by Factoring
Objective: TSW solve quadratic equations by
factoring using different methods. Sep 9­12:54 PM
FACTOR THE G.C.F
greatest.common.factor
Greatest Common Factor of 12 and 16
Find all the Factors of each number,
Circle the Common factors,
Choose the Greatest of those
Sep 9­12:54 PM
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U2C5.notebook
September 16, 2014
Sep 15­8:02 PM
Example: what are the factors of 6x2 − 2x = 0 ?
­ 6 and 2 have a common factor of 2:
2(3x2 − x) = 0
­ And x2 and x have a common factor of x:
2x(3x − 1) = 0
And we have done it! The factors are 2x and 3x − 1, We can now also find the roots (where it equals zero):
> 2x will be 0 when x = 0 > 3x − 1 will be zero when x = 1/3 Sep 9­12:54 PM
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U2C5.notebook
September 16, 2014
And this is the graph (see how it is zero at x=0 and x=1/3):
Sep 9­12:54 PM
Watch this! Factoring Quadratics Sep 9­12:54 PM
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U2C5.notebook
September 16, 2014
Sep 9­12:54 PM
1. x2 – 1
2. x2 – 25
3. x2 – 16
4. 4x2 – 25
5. 9x2 – 16
6. 81x2 – 49
7. 100x2 – 16
8. x2 – y2
9. 9x2 – 16
Sep 9­12:54 PM
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U2C5.notebook
September 16, 2014
1. x2 + 7x + 6
2. x2 + 7x + 12
3. x2 + 6x + 5
4. x2 + 12x + 36 5. x2 + 10x + 24
6. x2 + 12x + 27
7. x2 – 11x + 30
8. x2 – 15x + 56 9. x2 – 8x + 12
Sep 9­12:54 PM
1. 2x2 + 13x + 21
2. 3x2 + 17x + 20
3. 4x2 +27x + 18
4. 2x2 + 15x + 18
5. 2x2 + 17x + 36
6. 3x2 + 14 x+ 8
7. 3x2 – 10x + 8
8. 4x2 – 35x + 49
9. 3x2 – 13x + 14
Sep 9­12:54 PM
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