Why is this line not a horizontal shift of its parent function? If it is, how can I prove that?

Question

I took an algebra 1 quiz with a question that asked whether it was true or false that a line was a translation 3 units to the left of its parent function. I wrote an equation representing the transformation of f(X) into m(X) in which I applied a horizontal shift of 3 units to the left. When I checked the equation for accuracy to the graph, everything was correct. However, I was marked incorrect, and was told that the transformation was a vertical shift down 2 units. However, the horizontal shift and vertical shift create the exact same line, which is why I don’t understand why I’m incorrect. If I am correct, how can I prove that? Image of question