solving quadratic equations by factoring. solution by factoring example 1 find the roots of each...
TRANSCRIPT
Solving Quadratic Equations by Factoring
Solution by factoring
Example 1 Find the roots of each quadratic by factoring.
a) x² − 3x + 2 b) x² + 7x + 12 (x − 1)(x − 2) (x + 3)(x + 4)
x = 1 or 2. x = −3 or − 4 c) x² + 3x − 10 d) x² − x − 30(x + 5)(x − 2) (x + 5)(x − 6) x = −5 or 2 x = −5 or 6.
Now let’s solve these quadratics.
21) 24 144x x ( 12)x ( 12)x
12 0x 12 12
x 12
22) 10 21x x ( 3)x ( 7)x
3 0x 7 0x 3 3x 3
7 7x 7
e) 2x² + 7x + 3 f) 3x² + x − 2 (2x + 1)(x + 3) (3x − 2)(x + 1) x = -1/2 or −3 x = 2 or −1. 3 g) x² + 12x + 36 h) x² − 2x + 1 (x + 6)² ( x − 1)² x = −6, −6 x = 1, 1 A double root A double root.
a) x² = 5x − 6 b) x² + 12 = 8x
x² − 5x + 6 = 0 x² − 8x + 12 = 0
(x − 2)(x − 3) = 0 (x − 2)(x − 6) = 0
x = 2 or 3. x = 2 or 6.
c) 3x² + x = 10 d) 2x² = x
3x² + x − 10 = 0 2x² − x = 0
(3x − 5)(x + 2) = 0 x(2x − 1) = 0
x = 5/3 or − 2. x = 0 or 1/2.
Problem 6. Solve for x. a) 3 − 11x− 5x² = 0 2 5x² + 11x -3 = 0 2 10x² + 11x − 6 = 0 (5x − 2 )(2x + 3) = 0 The roots are 2 and −3
5 b) 4 + 11x − 5x² = 0
3 5x² − 11x − 4 = 0 3 15x² − 11x − 12 = 0 (3x − 4)(5x + 3 ) = 0 The roots are 4 and -3. 3 5
23) 7 10x x ( 5)x ( 2)x x 5 x 2
24) 10 30x x
Prime
25) 7 8x x ( 1)x ( 8)x x 1 x 8
26) 2 24x x
( 4)x ( 6)x x 4 x 6