Solving a two op-amp circuit
Start by forgetting about Vsrc and R, and just analyze the the two-opamp circuit by itself.  You should be able to see what each stage does from inspection, which then easily gives you what both stages together do.  Not even a calculator is needed here.

Now consider the input impedance of this circuit.  What is it?  It should also be obvious from inspection.  This gives you a certain current the two-opamp circuit will draw from its input for any particular voltage.  Now consider what voltage is on the right side or R for any particular input voltage.  This current thru R must be the same as that drawn by the inut for Vsrc to have no current thru it.

Now stop and think about what this circuit is really doing.  Start out with R infinite and consider what happens as R is lowered.  At inifinite R, this is just the basic two-opamp circuit that should be obvious.  Can you see that as R decreases, it supplies ever more current to the input?  The effect is that it increases the apparent input impedance of the overall circuit.  Eventually R gets to the point where all the input bias current is exactly offset, which is what this question is asking about.  At that point (ideally) you have a circuit with infinite input impedance.  If you keep going and make R smaller, you get something called hysterisis if Vsrc has any positive resistance.