The problem can also be solved by using the right section after making the cut. The free-body diagram for the right side section is as shown at the left. Notice, the 300 lb force is included on this section since the cut is to the left of the force. Summing the forces and moments give,
ΣFy = 0
V + By - F = 0
V = 300 - 150 = 150 lb
ΣMB = 0
-V L/2 + F L/2 - M = 0
M = -150 (8/2) + 300 (8/2) = 600 lb-ft
As expected, both methods obtain the same results, a shear force of 150 lb and a bending moment of 600 lb-ft.