Question 4 (0.5 points) A table of values of a linear function z=f(x,y) is given below: x=1.5 -O.25 -1.75 x=2 0.5 -1 . (a) Determine the linear function z=f(x,y). (b) Evaluate the function at (2,3), i.e., find f(2,3). Enter your answer in the blank below