A uniform beam of 6 m length and 300 n weight supports a 400 n load as shown below. Determine the tension in the supporting wire and the force exerted by the pivot on the beam.

Obviously the figure you tried to include in your post didn't load properly. But in any event - typically these kinds of problems require you to solve three equations in three unknowns: horizontal reaction forces sum to zero, vertical reaction forces sum to zero, and moments sum to zero. First thing to do is draw a free body diagram. The only "trick" is figuring out what point to caculate moments about - if there's a hinge at one end of the beam that's a good place to start.