What is the range of f (x) = 3x?

A. All positive real numbers

B. All real numbers greater than 3

C. All real numbers

D. All real numbers greater than or equal to 3

The answer is C : All real numbers. This means that y values can go up forever and down forever. Any linear graph has this quality.

A is wrong because the graph won't suddenly stop before going below the x axis

B is wrong because the slope is 3 which has no affects on the range

D is wrong for the same reason as b

We can replace x by any real number

so the range is also all real numbers

C