Let f(x) = 1/(x - 8). Find the largest x that is not in the domain of g(x) = f(f(x)).

Guest Jun 11, 2021

#1**0 **

Let f(x) = 1/(x - 8). Find the largest x that is not in the domain of g(x) = f(f(x)).

Key idea: Rational function : The denominator cannot be zero, any x value that makes denominator equal zero is not in the domain.

\(f(f(x)) = \frac{1}{(\frac {1} {x-8}) -8}\)

\(g(x) = \frac{1}{\frac{65-8x}{x-8}}\)

\(g(x) = \frac{x-8}{65-8x}\)

If (65 -8x = 0) that x value is not the domain of g(x)

65-8x = 0

x = (65/8) = 8.125 the largest x that is not in the domain of g(x)

Bginner Jun 11, 2021