3x 4y 2z=5
2x-y-3z=4
x 5y z=5

3x+4y+2z=5
2x-y-3z=4
z=5-x-5y

3x+4y+2(5-x-5y)=5
2x-y-3(5-x-5y) =4
z=5-x-5y

x-6y+5=0

5x+14y-19=0

z=5-x-5y

x=6y-5

5(6y-5)+14y-19=0

z=5-x-5y  

x=6y-5

y=1

z=5-x-5y

x=1

y=1

z=-1