### 2.9.1 Entering expressions in the editor: an example

The expression

x+2
x2−4

can be entered on the command line as:

(x+2)/(x^2-4)

You also can use the expression editor to enter it visually, as x+2 on top of x2−4. To do this, you can start the expression editor with the Alt+E keystroke (or the Expression ▸ New Expression menu command). There will be a small button M on the right side of the expression line, which is a menu with some commands use on the expressions. There will also be a 0 selected on the expression line and an on-screen keyboard at the bottom (see Section 2.2, item 2.2). If you type x + 2, it will overwrite the 0. To make this the top of the fraction, you can select it with the mouse (you can also make selections with the keyboard, as will be discussed later) and then type /. This will leave the x + 2 on the top of a horizontal fraction bar and the cursor on the bottom. To enter x2−4 on the bottom, begin by typing x. Selecting this x and typing ^2 will put on the superscript. Finally, selecting the x2 and typing - 4 will finish the bottom. If you then hit Enter, the expression will be evaluated and will appear on the output line.