3D Plotting using functions

I need to plot planes z=y^2, z=4-x and x=0 in the same figure using MATLAB and I have a hard time doing this.

[Mike Garrity]

I'm not making this an answer, because it's total overkill for planes, but I discussed the general case of implicit surfaces in this blog post.

http://blogs.mathworks.com/graphics/2015/03/03/implicit-curves/

That would work here, but there are much more efficient ways to do this particular case.