Using the graph of f(x) determine the value of f(4)

Given,
The grpah of the function is given in the question.
The value of f(x) is determined by the grpah.
So, at any point of x on the curve.
The coordnate of y gives the value of function.
So, at x= 4.
The curve is at y=0.
Hence, the value of f(4) is 0.