y = 4x+5 is in the form y = mx+b which is slope intercept form. Anything in y = mx+b form is linear. It graphs out a straight line.
Contrast this with y = x^2 which is nonlinear because it graphs a curve that isnt a straight line. All quadratics like this graph out a parabola which resembles a bowl shaped curve.
It is line/linear because for it to be a parabola the x would have to be squared.
This is what I got as my answer hope it helps!
Answer:
6.8
Step-by-step explanation: