Question

Find the values of x for which the combined function h(x) = is undefined if f(x) = 5x + 1 and g(x) = x2 - 9.

Answer 1

We need to know the definition of the "combined function" h(x).  I'm going to guess--by looking at answers--that the function is $h(x)=\frac{f(x)}{g(x)}$ making it

$h(x)=\frac{5x+1}{x^2-9}$

This function is undefined wherever the denominator is equal to 0 (division by zero is undefined).  Factor the denominator.

$h(x)=\frac{5x+1}{(x+3)(x-3)}$

The two values of x that make the denominator 0 are 3 and -3, otherwise written $x=\pm 3$.