Answer:
No
Reasoning:
There are two ways to figure this out.
1. You know when a function is linear when the equation is in the slope-intercept format. Which looks like

This does not look like that. So, it isn't a linear function.
2. Graph! If you graph the function, the graph will look like the figure below. It's not a line. This is called a parabola. Meaning, it's not a linear function.