nonlinear

I need to the solution of this example on Matlab. I try to solve, but stucked in the 3-uçlu (uçlu means outputs) nodal. How can i solve this problem?

If I have the following circuit how would I go about representing it in state space form, specifically the non-linear devices diodes, BJTs, and LEDs? Would I be correct in focusing on the non-linear devices linear acting region? Or do I take their V I relationship and linearize it?Thanks ahead...