Question

Решите систему уравнений: х-у=4, х^2-у^2=40;

Answer 1

$\left \{ {{x-y=4} \atop {x^2-y^2=40}} \right. \\ \\ x = 4 + y \\ \\ (4 + y)^2 - y^2 = 40 \\ \\ 16 + 8y + y^2 - y^2 = 40 \\ \\ 8y = 24 \\ \\ y = 3 \\ \\ x = 4+3=7$

Ответ: (7; 3)