X^2 + y^2 - 2x - 6y + 6 = 0
x + 2y = 3
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x = 3 - 2y
( 3 - 2y )^2 + y^2 - 2( 3 - 2y ) - 6y + 6 = 0
9 - 12y + 4y^2 + y^2 - 6 + 4y - 6y + 6 = 0
5y^2 - 14y + 9 = 0
D = 196 - 180 = 16 = 4^2
y1 = ( 14 + 4 ) : 10 = 1,8
y2 = ( 14 - 4 ) : 10 = 1
x1 = 3 - 2*1,8 = 3 - 3,6 = - 0,6
x2 = 3 - 2*1 = 1