Решите систему уравнений x-y=1 x^2+y^2=4-2xy
{ (x+y)² =4 ;x-y=1.⇔{ ( [ x+y = -2 ;x+y =2) ; x-y =1. а){x+y = -2 ; x-y =1 ⇒x= -1/2 ; y = -3/2. ----------------- б){x+y = 2 ; x-y =1 ⇒x=3/2 ; y =1/2