Question

Is the function linear or nonlinear?

Answer 1

The way you can tell if a function is linear or non-linear is if the rate of change is constant. Here you can tell it isn't the whole time.

-3 to -1 is +2

-1 to 0 is +2

0 to 1 is  +1 (Here is where the rate of change changes, making it non-linear.)

But just in case, let's check the y-values.

-5 to -1 is +4

-1 to 1 is +2 (Again, here is where you can tell)

Hope this helps!