Download Using the Quadratic Formula (7-6)

Solve Quadratic Equations by the Quadratic Formula (10.6)
 We learned that we can solve a quadratic equation by Factoring in Chapter 9.
x2 + 6x + 5 = 0
(x + 1)(x + 5) = 0
x+1=0
-1 -1
x = -1
x+5=0
-5 -5
x = -5
 Earlier this chapter we learned to solve a quadratic equation by graphing. The solution(s)
are where the parabola crosses the x-axis.
y = x2 + 6x + 5
Solutions:
x = _____ and x = ____
 To Solve Quadratic Equations in the form ax2 + bx + c = 0, where b  0 we can use the
Quadratic Formula:
 b  b 2  4ac 
x
2a
**Note: Be sure to put the equation
in standard form first.
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Ex. 2x2 + 4x – 7 = 0
Ex. x2 + 6x + 5 = 0
a = _____
b = _____
c = _____
a = _____
b = _____
 b  b 2  4ac 
x
2a
 b  b 2  4ac 
x
2a
Ex. 3x2 – 10 = -13x
Ex. x2 – 3x = 7
a = _____
x
b = _____
 b  b 2  4ac 
2a
c = _____
a = _____
x
b = _____
c = _____
c = _____
 b  b 2  4ac 
2a
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