120 has the same value as 12 tens
If you graph out y = x^2 - 1, you'll see that it is a curved parabola. It is not a straight line. So visually this shows the equation is not linear. It's considered nonlinear.
Algebraically, the given equation does not fit the form y = mx+b which is slope intercept form. So this is more confirmation that we do not have a linear function.
Buying books, your dorm and maybe a ride to get to school
