This mapping shows a functional relationship . when f(x)=4 , what is the value of x? 0. 2. 3. 4.

the answer is b

step-by-step explanation:

The domain consists of a pre image, and the range consists of the image. when we are looking at f(x), we are looking at the range. when we are looking at x, we are looking at the domain. when the range is 4, the x value is 2. 

so, when f(x) is 4, the value of x is 2.