First change UDL in to point load.
Resolved all the forces in horizontal and vertical direction. Since roller at B (only one vertical reaction) and hinged at point A (one vertical and one horizontal reaction).
Let reaction at hinged i.e., point B is RBH and RBV, and reaction at roller support i.e. point D is RDV Let ∑H & ∑V is the sum of horizontal and vertical component of the forces ,The supported beam is in equilibrium, hence
∑H = ∑V = 0
RH = RBH = 0
RBH = 0 ........(i)
∑V = RBV –50 –5 – RDV = 0
RBV + RDV = 55 .......(ii)
Taking moment about point B
50 × 0.5 – RBV × 0 – RDV × 5 + 5 × 7 = 0
RDV =12 KN
Putting the value of RBV in equation (ii)
RBV = 43KN
Hence RBH = 0, RDV = 12KN, RBV = 43KN.