# How to plot two or more equations simultaneously? [closed]

I have this two equations, and I want to solve them in a graphical way. So, -I'm thinking- how can I plot them at the same time?

• Read the help articles on ContourPlot and Solve. They will show you the way. – David Keith May 20 '19 at 0:08
• Plot[{3-2x, (4-x)/3},{x,0,1}]? – AccidentalFourierTransform May 20 '19 at 0:09
• Thanks. If I have equations with more than one variable, how can I set the range for each variable. I mean in this case you propose for x range ,{x,0,1}; what happen if I have x, y, z, etc? – Haizum Skallah May 20 '19 at 1:58
• The option PlotRange can be used to set the range for both variables. – m_goldberg May 20 '19 at 2:42
• does ContourPlot[{2 x + y - 3 == 0, x + 3 y == 4}, {x, -1, 3}, {y, -1, 3}, FrameLabel -> (Style[#, 12, Bold] & /@ {x, y}), MeshFunctions -> {Boole[2 # + #2 == 3 && (# + 3 #2 == 4)] &}, Mesh -> {{1}}, MeshStyle -> {Directive[Red, PointSize[Large]]}, PlotLegends -> Placed["Expressions", {.8, .9}]] work in your version? – kglr May 20 '19 at 5:14

pt = {x, y} /. Solve[{2 x + y - 3 == 0, x + 3 y == 4}, {x, y}][]

(* {1, 1} *)

Legended[
ContourPlot[
{2 x + y - 3 == 0, x + 3 y == 4},
{x, -1, 3}, {y, -1, 3},
FrameLabel -> (Style[#, 12, Bold] & /@ {x, y}),
Epilog -> {Red, AbsolutePointSize, Point[pt]}],
Placed[
LineLegend[
{ColorData, ColorData},
{2 x + y - 3 == 0, x + 3 y == 4}], {.7, .7}]] 