Graphical Behavior

Finding Zeros

Example

Find the zeros of the function: P(x) = x3 + 3x2 - 4x - 12

Step 1. Use a graphing calculator to make a graph of the function.

Zero_ex1

Step 2. Determine how many x-intercepts there are.

It appears there are 3 zeros or x-intercepts.

Step 3. Use the table to determine the zeros of the function.

When looking at the table, find the values of x for which y = 0. These are the x-intercepts or zeros of the function.

Zero_ex1-2

The zeros for this function are x = -3, x = -2, and x = 2.