I have a homework to deliver for one of my courses that consists of doing the nodal analysis of the following circuit, but I'm having a really hard time doing it. I made a schematic of the circuit on LTSpice and ran a simulation and I can't get the results shown there. I think my problem is getting to the equations. I got this:

(V_a+V_1-V_b)/R_2 + (V_a-V_b)/R_1 + V_a/R_4 =0,

(V_b-V_1-V_a)/R_2 + (V_b-V_a)/R_1 + (V_b-(V_c-V_3))/R_3 =0

(V_c-V_b)/R_3 + I_1+(V_c-V_2)/(R_6+R_5 )=0

The results I should be getting according to the simulation are: V(va): -0.47619, V(vb): -0.761905, V(vc): 1.33333

Can someone help me please?