Using Thevenin's theorem find the equivalent circuit for the given circuit. To find the Thevenin voltage find the voltage across the load terminals AB. Then to find the thevenin resistance short the source and find the resistance across the load terminals. Build a circuit with the thevenin voltage source and the thevenin resistance. This is the equivalent circuit and measure the voltage across the load terminals and verify that its same as that of the original circuit. Thus it is shown that it is an equivalent circuit.