The two linear equations are y=x/2 and y=2x-5.
They are linear because they are of the form y=mx+b. y=x/2 can be written as y=1/2x or y=1/2x+0.
y=2ˣ is an exponential function, since x is the exponent. It will graph as a smooth curve instead of a line.
y = x²+6 is quadratic since the highest power of x is 2. It will graph as a parabola, or u-shaped graph.