Answer:
The range is all real numbers.
Explanation:
The function shown is a line (and not a horizontal line).
The range is all the y's on the graph or all the y's that can be generated by the equation of the function.
f(x) = 3x + 9
You could put ANY, literally any, number in place of the f(x) and be able to calculate an x for it. Looking at the graph of this line, you could go up and down the y-axis to infinity in either direction, and the graph of the line would be there.
The range is All Real Numbers.