Among the given equation, (ax - by = k) is the example of a literal equation.
"A literal equation is an equation which consists primarily of letters. Formulas are an example of literal equations.
Given equations are:
A. ax - by = k: is a literal equation as per definition.
B. 8 - 2x = 14: is not a literal equation. It is a linear equation with variable 'x'.
C. 5x + 9y: it is not an equation.
D.4 + 12 = 42: it is not an equation.
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