Node analysis with voltage source, How to solve with matlab?
I just ignored G=1/R and wrote it with in-built functions like this instead:

E1 = 5;
E2 = 10;
J3 = 9;
R1=1;R2=2;R3=3;R4=4;R5=5;R6=6;R7=7;R8=8;

% Equation

syms Y2 Y3
eqn1 = ((Y2+E1)/(R1+R2))+((Y2-Y3+E2)/(R7+R6+R5))+((Y2-Y3)/R8)==J3;
eqn2 = -((Y2-Y3)/R8)-((Y2-Y3+E2)/(R7+R6+R5))+(Y3/(R3+R4))==0;

% Equation to matrix
[A,B] = equationsToMatrix([eqn1, eqn2], [Y2, Y3])

% format to decimals
A = vpa(A,4);
B = vpa(B,4);
% Solving matrix
U=A\B
Y2 = U(1)
Y3 = U(2)  


Answer:

A =

[  37/72,  -13/72]
[ -13/72, 163/504]


B =

 61/9
  5/9


U =

 17.1584
  11.297


Y2 =

17.1584

Y3 =

11.297