I didnt know how they knew the range and didnt understand it.any idea how and why? In addition how to become better at knowing domains and ranges .Thank you!

d) f(x, y) = 16 - 12 -12 Domain : The function f is well defined if its denominator is not zero which means if 16 - x2 - y? # 0,i.e. x2 + yz * 16. Thus DJ - -(x242= 16} mesh + to be? bexis Range : Let t E Ry and (x, y) ED , since the numerator is 1 so t * 0. Knowing that, 2 2 20=16- (x2 + y")