х+у=-7
х^2+y^2=25
1) x=-7-y
(-7-y)^2+y^2=25
49+7y+7y+y^2-25=0 ; 2y^2+14y+24=0 (:2); y^2+7y+12=0; D=49-48-1; D>0 ; y=(-7+1)/2 y=(-7-1)\2
y=-3
y=-4
2) x=-7-(-3)
X=-7+(-3)
x=-4
Вроде так............................
х+у=-7
х^2+y^2=25
1) x=-7-y
(-7-y)^2+y^2=25
49+7y+7y+y^2-25=0 ; 2y^2+14y+24=0 (:2); y^2+7y+12=0; D=49-48-1; D>0 ; y=(-7+1)/2 y=(-7-1)\2
y=-3
y=-4
2) x=-7-(-3)
X=-7+(-3)
x=-4
y=-3
x=-4
y=-3
Вроде так............................