4. Find the positive integer solutions of the indeterminate equation $3 x^{2}-7 x y-2 x-5 y-35=0$.
4. $y=-\frac{3 x}{7}-\frac{1}{49}+\frac{1710}{49(7 x-5)}$. Therefore, the solutions to the original equation are $(1,17),(2,3)$