Step 1:

Find the thevenins equivalent voltage.

1. Open the load resistor.

2. Calculate the Open Circuit Voltage. This is the Thevenin Voltage (V_TH).

Redraw the circuit :

The network has two independent loops.

Find the current in each loop.

Loop 1:

Apply KVL to the Loop 1:

.

Voltage at node A  :

.

Step 2:

Apply KVL to the Loop 2:

.

Voltage at node B  :

.

Step 3:

Find Thevenin Voltage .

Thevenin Voltage .

.

Therefore Thevenin Voltage is .

Solution :

Thevenin Voltage is .