Hello,

I have read that ContourPlot[] must be used for plotting implicit equations. Is it right?

Using ContourPlot[], the following code works right:

clr = {Green, Red};
plots = ContourPlot[{3 x^2 + y^2 - 9 == 0, 
    x^2 + y^2 - 1 == 0}, {x, -4, 4}, {y, -4, 4}, 
   ContourStyle -> Map[{clr[[#]], Thickness[0.005]} &, {1, 2}], 
   PlotLegends -> True, Frame -> True, FrameTicks -> False];   
Show[plots]

But it does not works when curves are grouped in a list:

clr = {Green, Red};
eqs = {3 x^2 + y^2 - 9 == 0, x^2 + y^2 - 1 == 0};
plots = ContourPlot[eqs, {x, -4, 4}, {y, -4, 4}, 
   ContourStyle -> Map[{clr[[#]], Thickness[0.005]} &, {1, 2}], 
   PlotLegends -> True, Frame -> True, FrameTicks -> False];   
Show[plots]

I am trying to write a module receiving a list of implicit curves and plotting them in a single graphics.

Any suggestion for making possible the second option?

Thanks in advance,

César Lozada