For my 3D graph project, my group decided to choose the equation: x + y + z = 3. I had to make the equation into -x + y - z = 3. Then I plug it in, for x-intercept I got (-3, 0, 0), y-intercept I got (0, 3, 0), and z-intercept I got(0, 0, -3). Then I graphed it onto a -X, Y, -Z graph to get the triangle plane.
As you can see the first picture, it's all of our graph assembled. The second picture is my part of the project by itself.