**Root/Zero of a Function**

The following concepts are synonymous: horizontal intercept, root of a function,
zero of a function.

Given *y* = *f*(*x*), a zero of *f* is an *x*-value such
that *f*(*x*) = 0.

Press
**MENU 3** to access the GRPH-TBL menu. Then enter
the function into the equation editor. For example, enter the function Y1 = x^{3}
- 3x^{2} - 6x + 8. Press **F5** to select DRAW. If needed, display
the graph in the standard viewing window by pressing **F2** to access the ZOOM
menu, highlight B:QUICK, press the right thumb pad arrow, select 7:Std, and press
**EXE**. The graph of the function in the standard
viewing window is shown at right.

Press **F4** to access the G-SLV menu, then press either **1** or **EXE**
to select 1:Root. The screen then displays the left-most root in the viewing window.
Moving from left to right, to display the next root, press the right thumb pad
arrow once. Continue in like manner to see more displayed roots.

**Note** Alternatively, one may obtain a zero of a function algebraically
rather than geometrically. To find the zeros for a function *f*, one may
solve the equation *f*(*x*) = 0.