1) {x^2+y^2=-21
     x+y=-3
2) {x^2+4y^2=34
    x+y=7   
reshite sistemu uravneniy

{x^2+y^2=-21x=-y-3(-y-3)^2+y^2=-21-(y+3)^2+y^2=-21-(y^2-6y+9)+y^2=-21-y^2+6y-9+y^2=-216Y=21+96y=30x=5{x^2+4y^2=34x=7-y(7-y)^2+4y^2=3449-14y+y^2+4y^2=345y^2-14y+15=0D=16x1=2.4x2=1