Today you will solve quadratic equations by graphing
But first, let's solve a linear equation by graphing!
Solve
2x + 5 = 11
by graphing:
# 7 on pg 625:
Solve by graphing: 2x 2 = 3x2 - 2x - 8
9.5
Solving Quadratic Equations by Graphing
Solve the equation by graphing.
2
x - 2x = 8
Step 1: Move all terms to one side of the equal
sign so the equation is equal to zero.
Step 2: Graph the related equation, y = x 2 - 2x - 8
Step 3: Graph the equation
Step 4: Look for the zeros (the x-intercepts)
The zeros are the solutions of the equation!
Graphing the Equation:
Axis of Symmetry:
Vertex:
y-intercept:
Another point:
**The zeros are the solutions to the equation,
so the solution(s) to the equation are:
Solve the equation by graphing:
x 2 + 36 = 12x
x 2 + 5x = -8
A baseball coach uses a pitching machine to
simulate pop flies during practice.
The baseball is shot out of the machine with a
velocity of 80 ft per sec.
The quadratic function y = -16t 2 + 80t
models the height of the ball after t seconds.
How long is the ball in the air?