1. Use the Quadratic Formula and the Discriminant
Section 4.8
Use the Quadratic Formula and the Discriminant

2. California Standard:
8.0: Students solve and graph quadratic equations by factoring, completing the square, or using the quadratic formula. Students apply these techniques in solving word problems. The also solve quadratic equations in the complex number system.
10.0: Students graph quadratic functions and determine the maxima, minima, and zeros of the function.

3. By following instructions, students will be able to:
OBJECTIVE(S):
By following instructions, students will be able to:
Solve quadratic equations using the quadratic formula.

4. QUADRATIC FORMULA: The solutions of the
equations are
Where and

5. EXAMPLE 1:
Solve

6. EXAMPLE 2:
Solve

7. EXAMPLE 3:
Solve

8. U-TRY#1:
Use the quadratic formula to solve the equation.
a) c) b) 8

9. Using the Discriminant of ax2+bx+c If , then the quadratic equation has two solutions (roots).

10. Using the Discriminant of ax2+bx+c If , then the quadratic equation has one solution (root).

11. Using the Discriminant of ax2+bx+c If , then the quadratic equation has no solution (root).

12. EXAMPLE 4:
Find the discriminant of the quadratic equation and give the number and type of solutions of the equation. a) b) c)

13. U-TRY#2:
Find the discriminant of the quadratic equation and give the number and type of solutions of the equation.
a) c) b) 13

14. HOMEWORK
Sec 4.8 WS