Question

Как решать такую систему?

Answer 1

$left { {{x-y=4} atop {x^2-y^2=40}} right. ; left { {{x-y=4} atop {(x-y)(x+y)=40}} right. ; left { {{x-y=4} atop {4(x+y)=40}} right. ; left { {{x-y=4} atop {x+y=10}} right. \\ left { {{2x=14} atop {2y=6}} right. ; left { {{x=7} atop {y=3}} right.$