Which equation represents a proportional relationship? y = 3x y=2(x+1/3) y=−3x+2 y=12x

The equation y = 3x and y = 12x represents a proportional relationship.
Because in a proportional relationship, the graph should pass the 0,0 coordinate.
 It means if you put x=0 to the equation, the result would be y=0. The graph will go in format of y=mx and if we put x = 0 in both equations we get y = 0
and in other two equations if you put x = 0 you will not get y = 0.

Answers: the graph is translated down 1 unit and the domain and range of g(x) is the same as the domain and range of f(x).