1. 4.8: Quadratic Formula HW: worksheet
Academy Algebra II
4.8: Quadratic Formula
HW: worksheet

2. Quadratic Formula
The quadratic formula is used to solve a quadratic equation.
Quadratic Formula: If ax2 + bx + c = 0, then

3. Discriminant The discriminant = b2 – 4ac
The value of the discriminant tells you how many solutions the quadratic equation has.
0  1 real solution.
positive number  2 real solutions.
negative number  2 imaginary solutions.

4. Find the discriminant and determine the number of solutions.
1.) x2 – 8x + 16 = 0
2.) 5x2 + 20x = -21

5. Use the Quadratic Formula to find the solutions to the equation.
3.) x2 – 4x – 5 = 0

6. Use the Quadratic Formula to find the solutions to the equation.
4.) 3 – 8v – 5v2 = 2v

7. Use the Quadratic Formula to find the solutions to the equation.
5.) 4x2 + 3 = x2 – 7x

8. How to Solve Quadratics
1.) ax2 + bx + c = 0 Ex: 4x2 + 10x – 11 = 0 2.) ax2 + c = 0 Ex: x = 0 3.) a(x + b)2 + c = 0 Ex: 3(x – 1)2 – 8 = 0

9. Solve the equation.
1.) 7x – 3x2 = x2 + 2x 2.) 3x2 + x – 4 = 5x +

10. Solve the equation.
3.) 25 – 16x2 = 12x(x + 5) 4.) = -8.5(2x – 1.75)2