So far the coefficients of our equations have been numbers. But nothing stops us from leaving some of them “undetermined”, represented by letters.
Definition — Literal equation
A literal equation is an equation in which, besides the unknown , one or more parameters appear (letters representing unspecified numbers). Solving it requires a discussion as the parameters vary.
The discussion is necessary because one and the same form can behave in different ways: dividing by a coefficient is permitted only if that coefficient is not zero, and it is precisely the parameter values that make it zero that generate the special cases to be treated separately.
Links
Topics: First-degree equations
Concepts: Parametric discussion · Literal equation · Parameter
Skills: Reasoning by cases · Solving equations