Chapter 2 - Functions and Their Graphs - 2.1 Functions - 2.1 Assess Your Understanding - Page 57: 55

{x|x \ne 4, x \ne -4}

g(x) = x / (x^{2} - 16) If the denominator is zero, the function is undefined. To make the function zero, x^{2} = 16 x = +-\sqrt 16 x=-4, x=4 X cannot then equal these values. Final answer: {x|x \ne 4, x \ne -4}