Answer:
nonlinear
Explanation:
If that's a fraction with an x on the bottom, it is non-linear.
Linear (graph is a line) has y = mx + b format or similar, with x having only a power of 1 (just plain x)
You get curves and other graphs when x is squared or higher exponent, or x inside a squareroot is also not a line. And, like your problem if x is on the bottom of a fraction it is nonlinear.