A function is defined for x and y such that f(x,y) = -2xy + y + x – 4…

Functions – – Ugh!

A function is defined for x and y such that f(x,y) = -2xy + y + x – 4. So, for x=2 and y=3, f(2,3)= -2x2x3+3+2-4 = -12+1 = -11. If x and y are to be chosen such that f(x,y) = f(y,x), then which of the following restrictions must be placed on x and y?

A) x>0 and y>0
B) x<0 and y<0
C) x = y
D) No restrictions are needed