Question

$left{ {{x^2+4y^2=34} atop {x+y=7}} right$

Answer 1

{x^2 + 4y^2 = 34
{x+y=7

{x^2 + 4y^2 = 34
{x=7-y

{(7-y)^2 +4y^2 = 34
{x=7-y

Решим первое уравнение:
(7-y)^2 +4y^2 = 34
49 - 14y + y^2 + 4y^2 = 34
5y^2 - 14y + 15 = 0
D1  =49 - 75 < 0 Решений нет