Solving the Quadratic Equations by the Quadratic Formula

1
Solving the Quadratic Equations by the Quadratic
Formula
Chapter 9.5

• Mrs. Cronquist
• Valley Christian High School
• Algebra 1B

2
The Quadratic Equation

• ax² bx c 0
• This is the form of the general equation. The
  letters a, b, and c stand for the coefficients of
  the different degrees of x in the equation.

3
Identifying a, b, and c

• Identify a, b, and c in the following equations
• x² 6x - 7 0 x² - 2x - 15 0
• 4x² - 8x 3 0 3x² x - 1 0

a b c
a b c
1 6 -7
1 -2 -15
a b c
4 -8 3
a b c
3 1 -1
4
Computing the Quadratic Formula

• Using the values you found for the first equation
  compute its solutions using the Quadratic Formula
• x² - 2x - 15 0
• Remember PEMDAS!

a 1 b -2 c -15
5
Computing the Quadratic Formula

• Using the values you found for the second
  equation compute its solutions using the
  Quadratic Formula
• x² 6x - 7 0
• Remember PEMDAS!

a 1 b 6 c -7
6
Computing the Quadratic Formula

• Using the values you found for the third equation
  compute its solutions using the Quadratic Formula
• 4x² - 8x 3 0
• Remember PEMDAS!

a 4 b -8 c 3
7
Computing the Quadratic Formula

• Using the values you found for the fourth
  equation compute its solutions using the
  Quadratic Formula
• 3x² x - 1 0
• Remember PEMDAS!

a 3 b 1 c -1
8
Writing Equations in Standard Form(ax² bx c
0)

• Rewrite the following equations in standard form
• 2x² -x 6 6x -8x² 2
• 3 3x² 8x 4x 3 - x²

(x) 2x² -x 6 (x)
2x² x (-6) 6 (-6)
2x² x - 6 0
(Always have a positive a or x² coefficient)
9
Homework

• 9.5 Page 536 537
• 23 80 every 4th Worksheet
• Due the 28th