Factoring and quadratics · Grades 11–12
Use the quadratic formula
Free worked example · No account needed
Example question
2x² + 3x - 2 = 0
Work through it
- 1
a = 2, b = 3, c = -2
Match the equation to ax² + bx + c = 0 before substituting.
- 2
x = (-3 ± √(3² - 4·2·(-2))) / (2·2) = (-3 ± 5) / 4
Substitute into x = (-b ± √(b² - 4ac)) / 2a and simplify the discriminant.
- 3
x = 1/2 or x = -2
Evaluate both choices from ±: (−3 + 5)/4 = 1/2 and (−3 − 5)/4 = −2.
Final answer
x = 1/2 or x = -2