Answer
$\displaystyle \frac{x+1}{3x-1}, \quad x\neq 0, \displaystyle \frac{1}{3}$
Work Step by Step
Complex rational expressions have rational expressions in the numerator or/and in the denominator.
Here, both the numerator and the denominator contain $\displaystyle \frac{1}{x}$ ( 0 is excluded from the domain). Multiplying each with x would get rid of the fractions.
$\displaystyle \frac{x}{x}\times\frac{1+\frac{1}{x}}{3-\frac{1}{x}}=\frac{x+1}{3x-1}, \quad x\neq 0, \displaystyle \frac{1}{3}$
