5x^2 + 5y^2 + 8xy + 2x- 2y +2 =0

manhquan318 wrote:

5x^2 + 5y^2 + 8xy + 2x- 2y +2 =0

5x^2 + 5y^2 + 8xy + 2x- 2y +2 =0
<=> (x^2 +2x +1) + 4.(x^2 + 2xy + y^2 ) + (y^2 -2y +1) = 0
<=> (x+1)^2 + 4.(x + y)^2 + (y-1)^2 = 0
<=> hệ ( x+1 = 0) & ( x +y = 0 ) & ( y -1 = 0 )
<=> x=-1; y=1