1. HW#8: Solving Quadratic Equations by Graphing: Baseball Path
SWBAT… use the Quadratic Formula to solve quadratic equations Tues, 2/ Happy Valentine’s Day!
Agenda
WU (10 min)
Quadratic Formula (20 min)
Warm-Up: Solve for x:
1. 2x2 – 6x + 3 = 0
HW#8: Solving Quadratic Equations by Graphing: Baseball Path

2. YOU MUST MEMORIZE THIS FORMULA!!!
The Quadratic Formula
YOU MUST MEMORIZE THIS FORMULA!!!

4. What Does The Formula Do?
The Quadratic formula allows you to find the roots of a quadratic equation (if they exist) even if the quadratic equation does not factorise.
The formula states that for a quadratic equation of the form :
ax2 + bx + c = 0
The roots of the quadratic equation are given by :

5. Example 1
Use the Quadratic Formula to find the exact solutions of the equations 2x2 – 6x + 3 = 0
a = 2 b = -6 c = 3
These are the roots of the equation.

6. Example 2
Use the quadratic formula to solve the equation x2 + 5x + 6 = 0
Solution:
x2 + 5x + 6 = 0
a = 1 b = 5 c = 6
x = -2 or x = -3
These are the roots of the equation.

7. Example 3
Use the quadratic formula to solve the equation 8x2 + 2x – 3= 0
Solution:
8x2 + 2x – 3 = 0
a = 8 b = 2 c = -3
x = ½ or x = -¾
These are the roots of the equation.

8. Example 4
Use the quadratic formula to solve the equation 8x2 – 22x + 15 = 0
Solution:
8x2 – 22x + 15 = 0
a = 8 b = c = 15
x = 3/2 or x = 5/4
These are the roots of the equation.

9. Example 5
What is wrong with this student’s work? What are the correct solutions?
Use the quadratic formula to solve the equation -2x2 + 5x + 3= 0
a = -2 b = 5 c = 3
x = ½ or x = -3/4
These are the roots of the equation.

10. x = -2/4 = -1/2 or x = 3 Example 5: Correct Solution
Use the quadratic formula to solve the equation -2x2 + 5x + 3= 0
a = -2 b = 5 c = 3
x = -2/4 = -1/2 or x = 3
These are the roots of the equation.