Given
z = 3
2y +z = 1
2x +3y +2z = 13
Find
x, y, z
Solution
... z = 3 is given
Substitute that into the second equation.
... 2y + 3 = 1
... 2y = -2 . . . . . subtract 3
... y = -1 . . . . . . . divide by the coefficient of y
Substitute these two solutions into the third equation.
... 2x +3(-1) +2(3) = 13
... 2x = 10 . . . . . . . . . . . . collect terms, subtract 3
... x = 5 . . . . . . . . . . . . . . divide by the coefficient of x
The variable values are: x = 5, y = -1, z = 3
