Question 55
Determine all pairs $(x, y)$ of real numbers such that
$$
\begin{aligned}
x^2 + x y - 4 y^2 &= -1 \\
4 x^2 + x y - 11 y^2 &= -2.
\end{aligned}
$$
$$
\begin{aligned}
x^2 + x y - 4 y^2 &= -1 \\
4 x^2 + x y - 11 y^2 &= -2.
\end{aligned}
$$
MathNet 2018-part-02 — 181 problems (EN–VI) Question 55
Math Olympiad Vault · MathNet 2018-part-02 — 181 problems (EN–VI)