Simple Static Loads Analysis

I am new to MathCAD and am doing a simple static force equilibrium analysis. My goal is to understand the best way to do this type of analysis so that I can then scale it to more complex problems. MathCAD document is attached (prepared in MathCAD Prime 3.0) and a scan of the sample problem that I’m working on is shown on the second page of the document.

I was able to get the correct result using Method-1 and Method-3 but I’m not able to get Method-2 to work. In Method-2 I’m attempting to make the resultant loads Bx and By (the variables I’m solving for) variables within a function called B. I’m then trying to call function B in the moment equilibrium equation to simplify the form of the equation. If I could get this approach (or something similar) to work it would be great because for more complex problems it would be very convenient to write equilibrium equations as a function of reaction load [B] where [B] represents Bxi + Byj + Bzk.

Also, as mentioned, Method-3 works but I don’t really understand the utility of this method if I need to manually enter the numeric coefficients into [M] and [v]. Is it possible to automatically populate the coefficients in [M] and [v] from the equilibrium equation shown in Method-1 and -2?

Another question is I’m interested in any recommendations to simplify my solution approach and / or apply best practices that others are using. For example – is it possible to do this evaluation without needing to explicitly define the unit vectors i, j, and k? Any other tips / suggestions?