#### Answer

(a) $$[B] = 6.00$$
(b) $$[B]= 6.00$$
(c) $$[B] = 9.00$$

#### Work Step by Step

1. Calculate the Kc using the first diagram:
(a) $$K_c = \frac{(4)^2}{(6)^2} = 0.444$$
(b) $$K_c = \frac{4}{6} = 0.667$$
(c) $$K_c = \frac{4}{6^2} = 0.111$$
2. Find "b" for equilibrium:
(a) $$[B] = \sqrt{(0.444)(9)^2)} = 6.00$$
(b) $$[B] = (0.667)(9) = 6.00$$
(c) $$[B] = (0.111)(9)^2 = 9.00$$