3. Solve the equation in integers: $\quad x^{2}-x y-2 y^{2}=7$.
Answer: $\{(3 ;-2),(5 ; 2),(-3 ; 2),(-5 ;-2)\}$

Solution: the solution to this problem is identical to the solution of the problem in variant 1 under the same number.

Note: 1 point for each correct solution found by trial and error.