1. x=6z+13/5
2. y= -2z-16/3
3. z= 6x/7+y/7+9/7
Explanations
1 Add 4x to both sides
5x=6z+13
Divide 5 by both sides
x=6z+13/5
2 Add 4z to both sides
-6y=32+4z
Divide 6 by both sides
-6y/-6 = 32/-6 + 4z/-6
Simplify
y=-2(z+8)/3 of y= -2z-16/3
3. Subtract 6x+y from both sides
-7z=-9-6x-y
Divide 7 by both sides
-7z/-7 = -9/-7 - 6x/-7 -y/-7
Simplify
z=6x/7+y/7+9/7