Pre-Calculus 11 Notes

By: Gen L.

Lesson 2: Solving Quadratics - Graphing

Terminology

• x-intercept(s) / Roots / Zeros: where the function crosses the x-axis ().
• Solving: finding the roots / zeros

Intro

• When solving a quadratic using a graph, it's just a matter of looking where the parabola crosses the x-axis.
• Note: Just because the values appear correct, take any values w/ a grain of salt, until you verify them.
• To verify: substitute both suspected answers in the equation and check if both sides balance.

Possible Results

• There are 3 possible situations you can answer.

1. 2 Real Roots: The function crosses the x-axis twice in two distinctive places.
2. 1 Real Root: The function crosses the x-axis in one distinct place. (often, the vertex is the root in this case)
3. 0 Real Roots: The function doesn't cross the x-axis in the real plane. ().

Next Lesson