Answer:
x = 7; y = 8; z = 5
Explanation:
x = 15 - y
y = 13 - z
z = 12 - x
The first equation is solved for x. Substitute x in the third equation with 15 - y from the first equation.
z = 12 - (15 - y)
z = 12 - 15 + y
z = y - 3 (Equation 1)
Now substitute y - 3 for z in the original second equation.
y = 13 - z
y = 13 - (y - 3)
y = 13 - y + 3
2y = 16
y = 8
Substitute 8 for y in Equation 1.
z = y - 3
z = 8 - 3
z = 5
Substitute 5 for z in the original third equation.
5 = 12 - x
-7 = -x
x = 7
Solution: x = 7; y = 8; z = 5