Rewrite
10x+y+z=12
2x+10y+z=13
2x+2y+10z=14
xn+1=101(12−yn−zn)
yn+1=101(13−2xn+1−zn)
zn+1=101(14−2xn+1−2yn+1)
Initial gauss (x,y,z)=(0.5,0.5,0.5)
1st Approximation
x1=101(12−0.5−0.5)=1.1
y1=101(13−2(1.1)−0.5)=1.03
z1=101(14−2(1.1)−2(1.03))=0.974
2nd Approximation
x2=101(12−1.03−0.974)=0.9996
y2=101(13−2(0.9996)−0.974)=1.00268
z2=101(14−2(0.9996)−2(1.00268))=0.999544
3rd Approximation
x3=101(12−1.00268−0.999544)=0.9997776
y3=101(13−2(0.9997776)−0.999544)=1.00009008
z3=101(14−2(0.9997776)−2(1.00009008))=1.000026464
Solution
x=1.000,y=1.000,z=1.000