Answer
z is not a function of x and y
Work Step by Step
Assume D to be a set of ordered pairs of real numbers. If to each ordered pair (x, 7) in D there corresponds a unique real number f(x,y), then f is called a function of x and y
So from the figure, you can say the same value of x and y their is two z values. Thus, we can say that the z is not a function x and y.
