The mapping diagram shows a functional relationship

Answer:
[tex]f(4)=\frac{1}{2}[/tex]
f(x) = 4 when x is 8
Step-by-step explanation:
Domain is the set of x values that make the function defined. Allowed x values for the function (mapping).
The Range is the set of y values that make the function defined. Allowed y values for the function (mapping).
Firstly, we need f(4), so we look for "4" in domain and see which number it corresponds to in range.
That is [tex]\frac{1}{2}[/tex]
Thus,
[tex]f(4)=\frac{1}{2}[/tex]
Next,
We want "x" value that gives us a "y" value of 4. We look for "4" in the range and see which value it corresponds to. That is "8". So,
f(8) = 4