The reaction at support A of the beam shown in below figure, is

The reaction at support A of the beam shown in below figure, is

 Solution

 Simply moment at pin and roller support is zero, but if you want to how to get its value.

Ray+Rby=1*10,Ray+Rby=10.
Then, take moment at support a,Ma =0,Rby*10-10*5=0, Rby=5
Then, Ray+Rby=10,Ray=5.
Take moment at A,Ma=10*5-Rby * 10,
Ma=10*5-5*10,
Ma=0.