Above system of equation can be written in matrix form as:
AX=B
X=A−1B
A=⎡⎢⎣23104−6569−20⎤⎥⎦,X=⎡⎢⎣uvw⎤⎥⎦,B=⎡⎢⎣412⎤⎥⎦, where u=1x,v=1y,w=1z
|A|=∣∣
∣∣23104−6569−20∣∣
∣∣=2(120−45)−3(−80−30)+10(36+36)=150+330+720=1200≠0
For adjA: A11=120−45=75
A12=−(−60−90)=150
A13=15+60=75
A12=−(−80−30)=110
A22=−40−60=−100
A32=−(10−40)=30
A13=36+36=72
A23=−(18−18)=0
A33=−12−12=−24
adj.A=⎡⎢⎣7511072150−10007530−24⎤⎥⎦T=⎡⎢⎣7515075110−10030720−24⎤⎥⎦
A−1=1|A|.adj.A=11200⎡⎢⎣7515075110−10030720−24⎤⎥⎦
⎡⎢⎣uvw⎤⎥⎦=11200⎡⎢⎣7515075110−10030720−24⎤⎥⎦⎡⎢⎣412⎤⎥⎦
⎡⎢⎣uvw⎤⎥⎦=11200⎡⎢⎣300+150+300440−100+60288+0−48⎤⎥⎦
⎡⎢⎣uvw⎤⎥⎦=11200⎡⎢⎣600400240⎤⎥⎦
⎡⎢⎣uvw⎤⎥⎦=⎡⎢
⎢
⎢⎣121315⎤⎥
⎥
⎥⎦
x=2,y=3,z=5