ANSWER
The function is not a linear function because the variable x is raised to the second power.
EXPLANATION
We want to describe the function:
[tex]y=x^2-1[/tex]
A linear function is one that has a straight line graph, in other words, it has a general form:
[tex]y=mx+b[/tex]
Therefore, the function is not a linear function because the variable x is raised to the second power.
