Chapter 4 - Exponential and Logarithmic Functions - Section 4.2 One-to-One Functions; Inverse Functions - 4.2 Assess Your Understanding - Page 292: 68

$ f^{-1}(x)=-\frac{4x+3}{x-2}$

Step 1. $f(x)=\frac{2x-3}{x+4} \Longrightarrow y=\frac{2x-3}{x+4} \Longrightarrow x=\frac{2y-3}{y+4} \Longrightarrow y=-\frac{4x+3}{x-2} \Longrightarrow f^{-1}(x)=-\frac{4x+3}{x-2}$ Step 2. Check $f(f^{-1}(x))=\frac{2(-\frac{4x+3}{x-2})-3}{(-\frac{4x+3}{x-2})+4}=x$ and $f^{-1}(f(x))=-\frac{4(\frac{2x-3}{x+4})+3}{(\frac{2x-3}{x+4})-2}=x$