Explain why z² =x+3y is not a function of x and y
a. The value of z is always positive for each ordered pair (x,y).
b. The value of z is always negative for each ordered pair (x,y).
c. The coefficient of x is equal to the coefficient of z² .
d. There is not a unique ordered pair (x,y) for each value of z.
e. The coefficient of x is less than the coefficient of y.
f. There is not a unique value of z for each ordered pair (x,y).