Plot contour map of the residual surface

Hello everyone! So I'm trying to 1)plot the contour map of the residual and energy surface, 2)3D plot the residual and energy surface given only a 2X2 A Matrix and 2x1 b Matrix. For example A= [1 2;1 0] b=[1;1]

Could anybody help me out? I'm not sure how to start this. Thanks in advance!

[Image Analyst]

Which (A or b) is the residual and which is the energy surface? It doesn't make much sense to plot a surface when you have only two (x,y) coordinates, like you have for A. A surface must have at least 3 points to form a plane. I think of residuals as the difference between your fitted data values and the actual (noisy) data values. What is your definition?