1)
2x+y=-12 y=-12-2x
x²+y²-2xy=9 (x-y)²=9
(x-(-12-2x))²=9
(x+12+2x)²=9
(3x+12)²=9
(3x+12)²-3²=0
(3x+12+3)(3x+12-3)=0
(3x+15)(3x+9)=0
3x+15=0 x₁=-5 y₁=-2
3x+9=0 x₂=-3 y₂=-6
Ответ: x₁=-5 y₁=-2 x₂=-3 y₂=-6.
2)
y-x=-2 y=x-2
(x-1)²+(y-2)²=9 (x-1)²+(x-2-2)²=9 (x-1)²+(x-4)²=9
x²-2x+1+x²-8x+16=9
2x²-10x+8=0 |÷2
x²-5x+4=0 D=9
x₁=4 y₁=2
x₂=1 y₂=-1
Ответ: x₁=4 y₁=2 x₂=1 y₂=-1.