Warm Up – System of Equations Write equations that represent the costs of printing digital photos at each lab. Under what conditions is the cost to print digital photos the same for either store.

The Quadratic Formula 5-6 SWBAT: Solve quadratic equations using the Quadratic Formula. Classify roots using the discriminant. Holt Algebra 2

You have learned several methods for solving quadratic equations: graphing, making tables, factoring, using square roots, and completing the square. Another method is to use the Quadratic Formula, which allows you to solve a quadratic equation in standard form. By completing the square on the standard form of a quadratic equation, you can determine the Quadratic Formula.

Discriminant b2 – 4ac > 0 & a perfect square 2 real, rational roots Discriminant: is the radicand in the quadratic formula. It is the part of the Quadratic Formula that you can use to determine the number of real roots of a quadratic equation. b2 – 4ac > 0 & a perfect square 2 real, rational roots b2 – 4ac > 0 & not a perfect square 2 real, irrational roots b2 – 4ac = 0 1 real, rational root b2 – 4ac < 0 2 complex roots

Make sure the equation is in standard form before you evaluate the discriminant, b2 – 4ac. Caution!

Analyzing Quadratic Equations by Using the Discriminant Find the type and number of solutions for the equation. Do not solve completely. b. x2 + 30 = 12x a. x2 + 40 = 12x c. x2 – 4x = –4 d. x2 – 4x = –8

Pg 281 #11-14 For part b, only do the first part. HOMEWORK Pg 281 #11-14 For part b, only do the first part.