Question

решите систему y-x＝-3 x2-y2＝63​

Answer 1

$\left \{ {{y-x=-3} \atop {x^{2}-y^{2}=63}} \right.\\\\\left \{ {{x-y=3} \atop {(x-y)(x+y)=63}} \right.\\\\\left \{ {{x-y=3} \atop {3(x+y)=63}} \right.\\\\+\left \{ {{x-y=3} \atop {x+y=21}} \right.\\------\\2x=24\\\\x=12\\\\y=x-3=12-3=9$

Ответ :(12 , 9)