What is the key difference between the graph of a linear relationship and the graph of a nonlinear relationship?
what is the key difference between the graph of an exponential relationship and the graph of a quadratic relationship?

Linear functions are in the form of where 'm' is the slope and b is the y intercept. Linear functions are graphed as straight lines, whereas the graph for a non-linear relationship is curved. A non-linear relationship tells that if 'x' intercept changes this does not always make same change in the y variable.

The quadratic relationships are in the form .  In quadratic functions the x is squared. The graph of quadratic equation is a parabola.

In exponential relationship, as the value of x increases, the value of f(x) also increases proving that the function is an increasing function. The inverse of an exponential function is a logarithmic function. The exponential is shown as : where b > 0 and that b ≠ 1.