Linear or nonlinear

Question

3.1 = 3x=0

Answer 1

I am not sure what you are asking here. Both 3.1-3x=0 and 3x=0 are equations that we would solve for x, not functions relating an independent variable x to some dependent variable, like y. Thus, neither 3.1-3x=0 nor 3x=0 can be called linear or non-linear.