Sum moments about A to compute the reaction force at B:
↺+∑ МA=3 kN/m(2 m)(1 m)-(2 kN/m)(8 m)(4 m) +(5 kN)(2 m)+(8 m) By=0 ∴By=6 kN
Determine the reaction force at pin A by summing forces in the vertical direction: