A
There is no variable (x or y) that is raised to any power but 1. This is linear.
B
One thing you could do and that is try to graph it. The table is entered below. I haven't made the table yet, so I don't know if it is linear or not. My instincts tell me not. And that turns out to be correct. It looks like a quadratic of some kind. The diagram on the right is a better picture of the quadratic.