## Zero Option

The zero option is used to find an x intercept. Press .

Press .
(The zero option can also be obtained by using the
to select option 2 and pressing .)
Since a function may have more than one x intercept, specify an interval
containing the desired x intercept. (The equation in the upper left-hand
corner indicates finding an x intercept on the graph of the second function.)

The question "Left Bound?" appears at the bottom of the screen. Use
the
to move the blinking cursor to the *left* of one of the x intercepts.
Press .

The question "Right Bound?" appears at the bottom of the screen. Use
the
to move the blinking cursor to the right of the x intercept.
Press .

The arrows at the top of the screen indicate the boundaries between
which the calculator will give the root. (The arrows must point toward
each other and an x intercept must lie between them.) The question "Guess?"
appears at the bottom of the screen. Locate the cursor between the established
boundaries. Press .

The coordinates of the x intercept appear at the bottom of the screen.
In this case the x intercept is about 9.02.

**Note:** For a specific example using the zero option, read Exercise 4 of the Skill
Building Exercises in the Prologue of *Precalculus: Making Connections*
.