I'm struggling with the following question:

Question

The opening of chloride selective channels by a neurotransmitter X will drive membrane potential toward the chloride equilibrium potential. Assume that early during cell development, Cl is pumped into the cell for a concentration [Cl]i (intracellular) of 60 mM. The external concentration is always 140 mM. Also assume body temperature, as well as internal and external concentrations of the following ions respectively:

K(+)= 140 in, 5.3 ex
Na(+)= 10 in, 154 ex
Ca(2+)= 0.0001 in, 1.8 ex

We were only taught the nernst potential equation, and the Goldman (GHK) equations.

a) If a neuron is voltage clamped at -70 mV and you applied X, is the X-induced current inward or outward, and does this imply Cl influx or efflux?

b) If X channels remained open, what would be the steady state concentration of intracellular Cl after a few minutes voltaged clamped at -70 mV?

c) If you switch to current-clamp mode and put X on the cell, how would the membrane potential change? Assume a resting potential of -70 mV. Is X inhibatory or excitatory?

So for a, I'm thinking to use the outward flux (GHK) equation since Cl is flowing into the cell. But I'm not given a permeability value so I don't see how I can use it. To be honest, I'm not even sure what specific value I need to answer this question. Do I just need to find the sign of the current?

For b, I'm thinking of setting the inward and outward current equations (also GHK) equal to each other, and then solve for intracellular concentration of Cl. Is this right? I'm not sure if I can do that when the cell is at steady state, because I'm assuming that would only be allowed for an equilibrium state (or is equilibrium and steady state the same thing when it comes to this stuff?)

And I flat out don't know how to do c. I can't think of how I can get any of equations to work for it.

Can anybody help me here? I don't need help with the math, but recognizing what the problem is giving me and how to set up the equations/solutions is what's holding me back. I'd appreciate any help.