Return to the Solver Editor screen and modify the equation to read Z=L(X , Y^2) + G(X). Then press <ENTER> F9. Once again, X has disappeared from the list of variables, because it is the first argument of L(,) and it is the argument of G(). (In the above formula, if you let Y=4 and solve for Z by pressing <Space Bar> when Z is highlighted, you find that Z=32. You add 42, which is 16, to X, which has been assigned the value of 16 by the L(,) function of the equation -- 16+16=32.)