Press `MODE`
Select `1: COMP`
Press `SHIFT`
Press `CALC`
Enter the value for `x`
Press `=`
To change `x` again, press `SHIFT`
Press `CALC`
Enter the new value for `x`
Press `=`
To clear...
Press `SHIFT`
Press `MODE` (SETUP)
Select `Fix`
Enter the number of decimal places you want
Press `=` if needed to confirm
Enter your calculation to display answers in decimal...
