Answer
$\frac{x+1}{3x-1} ; x\ne 0, \frac{1}{3}$
Work Step by Step
$\frac{1+\frac{1}{x}}{3-\frac{1}{x}} = \frac{\frac{x+1}{x}}{\frac{3x-1}{x}} ; x\ne 0, \frac{1}{3}$
$= \frac{x+1}{x} \times \frac{x}{3x-1};x\ne 0, \frac{1}{3}$
$= \frac{x+1}{3x-1} ; x\ne 0, \frac{1}{3}$
