What is the quadratic formula ? Definition and examples.

The quadratic formula is the formula that we use to solve a quadratic equation that has the form :  ax² + bx + c = 0

Notice that a cannot be equal to 0 since any number divided by 0 has no answer or is undefined.

Notice also that b² - 4ac has to be at least 0.

How to use the quadratic formula

Solve 2x² - 3x + 1

a = 2, b = -3, and c = 1

b² - 4ac = (-3)² - 4(2)(1) = 9 - 8 = 1

√1 = 1

x = (- -3  ± 1) / 2(2) 

x = (3  ± 1) / 4

x₁ = (3 + 1) / 4 = 4 / 4 = 1

x₂ = (3 - 1) / 4 = 2 / 4 = 0.5