x Which function is linear?

A f(x) = 3/(2x) + 1/2

B f(x) = |3/2 * x| + 1/2

C f(x) = (3/2 * x) ^ 2 + 1/2

D f(x) = 3/2 * x - 1/2

D f(x) = 3/2 * x - 1/2

This function is linear because it is in the form y = mx + b, where 'm' is the slope (3/2) and 'b' is the y-intercept (-1/2).