The following problems require the use of the algebraic computation of limits of functions as x approaches a constant. Most problems are average. A few are. When your pre-calculus teacher asks you to find the limit of a function algebraically, you have four techniques to choose from: plugging in the x value, factoring. Sal finds the limit of (x²+x-6)/(x-2) at x=2 by factoring and simplifying the expression.