1. The problem statement, all variables and given/known data http://img706.imageshack.us/img706/263/hwstatement.png [Broken] 2. Relevant equations KCL/Node voltage method Ideal op-amp rules 3. The attempt at a solution I solved a previous, similar problem where the gain was fixed and the resistor mass going into the inverting and noninverting inputs of the opamp was merely a single resistor from each lead of Vi. The way I've been attempting to solve this problem is by assigning unknown voltages (say V1, V2) to each of the leads of Vi, assigning two more unknowns to the top and bottom nodes of Rg (say, Rg1, Rg2), and another unknown voltage to the inverting/noninverting potential (say, Vb). Then, I find the node equations using KCL and attempt to solve. The resulting equations are extremely unwieldy and I feel like there must be a better way to approach this problem.