a) Use mesh analysis to find V_o.

b) Find the power delivered by the dependent source.

iD = I₃

There are no current sources, thus no supermeshes.

Write KVL around each mesh.

Mesh 1:

2 I₁ + 16 (I₁ - I₂) - 10 = 0

18 I₁ - 16 I₂ + 0 I₃ = 10 (Eq. 1)

Mesh 2:

12 I₂ + 4 iD + 16 (I₂ - I₁) = 0

12 I₂ + 4 I₃ + 16 (I₂ - I₁) = 0

- 16 I₁ + 28 I₂ + 4 I3 = 0 (Eq. 2)

Mesh 3:

5 I₃ + 3 I₃ - 4 = 0

0 I₁ + 0 I₂ + 8 I₃ = 4 (Eq. 3)

Solving the three equations yields:

I₁ = 1 A

I₂ = 0.5 A

I₃ = 0.5 A

Therefore

V_o = 16 (I₁ - I₂)

V_o = 8 V

and for the dependent source,

P_del = - 4 (iD) (I₂)

P_del = - 4 (I₃) (I₂)

P_del = - 1 W

Thus the dependent source is actually absorbing power.