Question

Пожалуйстаааааааа:)))

Answer 1

$left { {{x+y=10} atop {x^2-y^2=40}} right. \ left { {{x=10-y} atop {(10-y)^2-y^2=40}} right. \ (10-y)^2-y^2=40 \ 100-20y+y^2-y^2=40 \ 20y=60 \ y = 3 \ left { {{y=3} atop {x=7}} right.$