1. The problem statement, all variables and given/known data 2. Relevant equations V(oc) = I(sc) * R(th) Kirchoff's voltage law 3. The attempt at a solution a) is okay. For part b): After redrawing with the R(th) and V(th) found in part a): Equations of loops: s is I(sc) a is I(left loop) left loop: -8 + a(4000) + (a-s)(4000) = 0 right loop: (s-a)(4000) - (2000)x = 0 I(x): a-s = x I(sc) comes out to 0.2 mA Then V(oc) = I(sc) R(th) 4 V = (0.002 A) R(th) R(th) = 2 kOhm = R(L max) However, this is 1 kOhm off from the answer. What is the problem with the above working? Thank you very much.