The mapping diagram shows a functional relationship

Answer:[tex]f(4)=\frac{1}{2}[/tex]f(x) = 4 when x is 8Step-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).Whenever we need to find f(a), suppose, then we look for "a" in the domain and see its corresponding value mapping in the range.Whenever we will be given a value for f(x) = a, suppose, and we have to find "x", we look at the value a in the range and find corresponding x value in the domain.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