Download Solving Quadratics Review We must solve to get x 2 by itself 1 st

Solving Quadratics Review
We must solve to get x2 by itself 1st!
3x  48  0
2
3 x  48
2
x  16
2
x  4
Ex. 1: Solve the equation x2 – x -20 = 0
STEP 1: Factor and set each factor equal to zero.
(x-5)(x+4)=0
x-5= 0 and x+4 = 0
STEP 2: Solve for x.
x-5= 0
x=5
x+4 = 0
x=-4
Solving with GCF
•
•
•
•
•
Example 2: 6x2 + 30x + 36=0
GCF?
6
6(x2 + 5x + 6)=0
Can be x2 + 5x + 6 factored?
x2 + 5x + 6 can be factored to (x + 3)(x + 2)
• 6(x + 3)(x + 2)=0
• Answers: x = -3 x = -2
2
6x
Solve:
– 11x + 3=0
(2x – 3) (3x – 1) = 0
x = 3/2 x = 1/3
1s
Ex: Solve x2+ 6x +10 = 0
t
 b  b  4ac 6  6  4 110

x
2 1
2a
nd
a=
6  36  4 110 6  236

40


b=
2 1
2
2
2
c=
6  4 6  2i  6  2i and 6  2i


2
2
2
2
 3  i and  3  i
Solve
1) x2 + 5x + 6 = 0
2) x2 – 2x – 8 = 0
3) x2 + 7x + 6 = 0
4) 6x2 + 15x = 0