x^2+3y^2+4x-6y=50
Solution :
x=r*cos(t)
y=r*sin(t)
where t=angle build by positive x-axis cartesian coordinate to line connected from origin to the point.
x^2+4x+4+3y^2-6y+3=50+4+3
(x+2)^2+3(y-1)^2=57
[r*cos(t)+2]^2+3[r*sin(t)-1]^2=57*[sin^2(t)+cos^2(t)]