More about Quadratic Equations

November 16, 2009

Objectives

• Understand basic concepts about quadratic equations.

• Use factoring, complete the square, and the quadratic formula to solve quadratic equations.

• Understand the discriminant.• Solve problems involving the quadratic

equations.

What is a quadratic equation?

• It is:

ax2+bx+c=0• If you solve for x, what

are you finding on the graph?

• Where y=0, aka the x-intercepts

Completing the square

• x2+4x-1=0

The quadratic formula

x= -b ± √b2-4ac

2a

3x2+10x-1=0

The discriminant

• The discriminant is:

b2-4ac• If b2-4ac >0, there are two real

solutions.• If b2-4ac = 0, there is one real solution.• If b2-4ac <0, there are NO real solutions.