Finding the Thevenin equivalent resistance in given circuit
I'm not going to just do your homework for you.  However, consider what the impedance of a voltage source and a current source are.  Since you're only looking for the impedance, voltage and current offsets don't matter.  Replace the voltage sources with shorts and the current sources with opens.

After you redraw the circuit as above, it comes down to solving a resistor mesh.  Look for series and parallel resistances to combine, and proceed the usual way to solve a mesh.