#### Answer

$\frac{18x}{17}+3$

#### Work Step by Step

We can write any fraction as a sum or a difference if multiple things are added or subtracted in the numerator (top of the fraction). In order to write the fraction as a sum or difference, we simply take the numerator and break it into two separate fractions, each one with the same denominator (bottom of the fraction) as the original fraction. In the problem, the numerator is 18x+51, so we add the two fractions, coming to the final answer:
$\frac{18x}{17}$+$\frac{51}{17}=\frac{18x}{17}+3$.