x+y=2 x2+y2=100 x=2-y (2-y)2+y2=100 4-4y+y2+y2-100=0 2y2-4y-96=0 y2-2y-48 D=4+4*48=196 D=14 y1=2+14/2=8 y2=2-14/2=-6 x1=2-8=-6 x2=2+6=8 (8;-6) (-6;8)