Press to type the variable x.
Press to type a leading negative sign.
Press to type a subtraction symbol.
A equation can be selected or deselected by moving the cursor to the equal sign of that equation and pressing . Deselected equations still exist but are not graphed.
Any character in an equation can be deleted. Highlight the character and press .
Characters can be inserted in an equation. Highlight the entry after which the characters are to be inserted. Press .