\[\frac{(y - 18)^{\backslash y}}{6y^{2}} - \frac{2 - 3y^{\backslash 6}}{y^{3}} =\]
\[= \frac{y^{2} - 18y - 12 + 18y}{6y^{3}} =\]
\[= \frac{y^{2} - 12}{6y^{3}}.\]