To calculate f(x) for a given x, follow these steps. 

1. Enter the function: Press c to open the Y= editor.
   
   
2. Input the function: Enter your function f(x). Remember to use l to get the x variable and − for negative numbers.
   
   
3. Press g then type the desired value of x and press =. The calculator will display the corresponding y-value and the cursor jumps to the corresponding coordinate.