\[3\frac{3}{7} \cdot 2\frac{5}{8}y + 1\frac{3}{4} = \frac{24}{7} \cdot \frac{21}{8}y + 1\frac{3}{4} =\]
\[= 9y + 1\frac{3}{4};\]
\[y = \frac{2}{9}:\]
\[9 \cdot \frac{2}{9} + 1\frac{3}{4} = 2 + 1\frac{3}{4} = 3\frac{3}{4}.\]