Calculating Forces and Moments for Static Equilibrium of a Structure

[Uhmazuba]

So I have to do this question and I attempted this.
Can anyone go over this and see if I did it correctly. Another student from my class told me I had to use the torque in order to calculate Fab but I don't see how I would do that.

 

[SteamKing]

In order for the frame to be in static equilibrium, the sum of the forces and the sum of the moments about point A must each equal zero.

Your calculations appear to use only the sum of the forces. You need to write a moment equation about point A in order to solve this problem.

In simple terms, the moment of M about point A is balanced by the moment about point A of the normal force on the rollers at point B.