Solving quadratics of the form x2 + bx + c = 0 − using the quadratic formula
Solving quadratics of the form ax2 + bx + c = 0 using the quadratic formula:
| x = |  |
In the examples that follow a is always equal to 1
Example 1. Solve x2 + 7x + 6 = 0
Example 2. Solve x2 − 11x + 30 = 0
Example 3. Solve x2 + 2x − 8 = 0
Example 4. Solve x2 − 5x − 24 = 0
x2 + 7x + 6 = 0 here a = 1, b = 7 and c = 6
Verify by putting these two values of x into x2 + 7x + 6
x2 − 11x + 30 = 0 here a = 1, b = − 11 and c = 30
Verify by putting these two values of x into x2 − 11x + 30
x2 + 2x − 8 = 0 here a = 1, b = 2 and c = − 8
Verify by putting these two values of x into x2 + 2x − 8
x2 − 5x − 24 = 0 here a = 1, b = − 5 and c = − 24
Verify by putting these two values of x into x2 − 5x − 24
to: 
