The general equations describing a linear function is written as
[tex]\begin{gathered} y=mx+b \\ ax+by=c \end{gathered}[/tex]Based on the options given, letters A and C exhibit the same formula structure with y = mx + b while letter B has the same structure as ax + by = c. This means that these equations are considered a linear function.
Letter D is not considered a linear function since it does not follow the general structure of a linear function.
Answer: D
