Question

$left { x^{2} - y^{2}=13 } atop{ x-y=1 right.$

Answer 1

Решение смотри на фото

Answer 2

$left { {{x^2-y^2=13} atop {x-y=1}} right.\\ left { {{x=y+1} atop {(y+1)^2-y^2=13}} right.\\ y^2+2y+1-y^2-13=0\2y-12=0\\y=6\x=6+1=7\\ left { {{y=6} atop {x=7}} right.$