EQ. 1: x+y-z = 1
EQ 2: x +2z =0
EQ. 3: 2x+2y=4
Solve for X in EQ. 2: x +2z=0, subtract 2Z from each side:
x = -2Z
Replace X in EQ. 1 with solution of EQ 2 and solve for Y:
-2z + y -z =1
Simplify:
-3z +y = 1
Add 3z to each side::
y =3z +1
Replace X and Y in EQ.3 and solve for Z:
2(-2z) +2(3z+1) = 4
Distributive property:
-4z + 6z +2 = 4
Simplify:
2z +2 = 4
Subtract 2 from each side:
2z = 2
Divide both sides by 2:
z = 1
Now replace z with 1 and solve:
X = -2z = -2(1) = -2
Y = 3z +1 = 3(1) +1 = 3+1 = 4
Z = 1
Solution is (-2,4,1)