Answer
$-\dfrac{1}{3y^2}$
Work Step by Step
Adding the numerators, copying the denominator, and then cancelling the common factor between the numerator and the denominator result to
\begin{array}{l}
\dfrac{x}{3y^2}-\dfrac{x+1}{3y^2}
\\\\=
\dfrac{x-(x+1)}{3y^2}
\\\\=
\dfrac{x-x-1}{3y^2}
\\\\=
\dfrac{-1}{3y^2}
\\\\=
-\dfrac{1}{3y^2}
.\end{array}
