Lesson 1 of 8High school~14 min

Quadratic Equations - the Formula

Solving ax² + bx + c = 0 with the discriminant

You should already know:Expanding Binomials

Completes automatically at 90 % watched

After this lesson you'll be able to:

Rearrange an equation into ax² + bx + c = 0 and read off a, b, c with their signs
Compute the discriminant D = b² − 4ac and use it to tell how many solutions there are
Substitute into the formula x₁,₂ = (−b ± √D) / 2a and work out both solutions
Check a solution by substituting it into the original equation