Quadratic Formula & Discriminant

It’s called finding the discriminant. There is a way to tell how many solutions/roots an equation will have. It’s called finding the discriminant. The discriminant is a small part of the quadratic formula.

Put in standard form first!  If the answer is POSITIVE, then you will have 2 real roots.  If the answer is ZERO, then you will have 1 real root.  If the answer is NEGATIVE, then you will have 2 imaginary roots. Put in standard form first!

Determine the number of roots. Example: 1 2 Imaginary Roots

Determine the number of roots. Example: 2 1 Real Root

Determine the number of roots. Example: 3 2 Real Roots

Quadratic Formula Everything must be on the same side of the equals sign before solving and a is positive.

1st Ex: 1 Solve x2 + 9x + 14 = 0 a = 1 b = 9 c = 14 2nd

Ex: 2 Solve x2 + x = 1 a = 1 b = 1 c = -1

Ex: 3 Solve -2x2 = -2x + 3 a = 2 b = -2 c = 3

Class Work SPW 222 “What do you call it when somebody spends 20 years in the 24th row of a theater?”

Homework p. 93 #1 – 10, 15, 16