Question

Решите систему уравнений:
$left { {{x-y=2 atop {x^2-y^2=8}} right.$

Answer 1

$left { {{x-y=2 atop {x^2-y^2=8}} right. Leftrightarrow left { {{x-y=2 atop {(x-y)(x+y)=8}} right. Leftrightarrow 2(x+y)=8; Leftrightarrow x+y=4;$

$left { {{x=2+y atop {x+y=4}} right. Leftrightarrow 2+y+y=4; Leftrightarrow y=1; Leftrightarrow x=3;$