Answer
$= \frac{3y - 4x - 5}{xy}$
Work Step by Step
1) Multiply a fraction with the other denominator to obtain a common denominator between the three fractions. In this case, we multiply the first fraction by $y/y$, the second fraction by $x/x$, and the third fraction we simply leave alone as we already have a common denominator of $xy$
2) Subtract
$= \frac{3}{x} - \frac{4}{y}- \frac{5}{xy}$
$= \frac{3y}{xy} - \frac{4x}{xy}- \frac{5}{xy}$
$= \frac{3y - 4x - 5}{xy}$
