Depending on what you are doing, you may be able to press the STO> button, type a letter, hit enter, and store the decimal value as a variable which you can then use from the homescreen.
If you are finding x values, you can just use the 'x' button and x will still have the value you found.
I don't remember the exact command, but there should be an "evaluate function" command that can find the value you need without graphing.