Question

Решите систему уравнений:
$left { {{3 x^{2}+y = 9 }, atop {7 x^{2} -y=1}} right.$

Answer 1

$left { {{y=9-3x ^{2} } atop {7x ^{2}-(9-3 x^{2} )-1=0 }} right.$
$7 x^{2} +3 x^{2} -10=0 10 x^{2} =10 x^{2} =1 left { {{x=1} atop {x=-1}} right.$
$left { {{y1=9-3=6} atop {y2=9+3=12}} right.$
Ответ: x1=1;x2=-1;y1=6;y2=12