The domain is the input (x) value. This can be any real number so the domain is (-∞, ∞).
The range is the output value (y) since the input is any real number, the range would also be any real number, the range is (-∞, ∞).
to graph the equation, find the x and y intercepts by replacing x qith 0 and solve for Y, and replace y with 0 and solve for x. This gets you two points to put on the graph, then draw a line through the two points.
X intercept = (0,-3)
Y intercept = (4.5,0)
See picture for the graph.