Verified answer

{ y=3x+1                            { y=3x+1

x²-2x(3x+1)+(3x+1)²=9     x²-6x²-2x+9x²+6x+1-9=0

{ y=3x+1               { y=3x+1         { y=3x+1

4x²+4x-8=0|:4      x²+x-2=0       x1=-2

{x1=-2

x2=1

y1=3*(-2) +1

y2=3*1+1

y1=-5

y2=4

Ответ: (-2;-5) ;(1 ;4)