Order of operations is not as applicable in this situation because we're just dealing with addition and subtraction. This is a simple case of plugging in values for the given expression.
x = 3
z = 4
So it becomes...
3 + 3 - 4
6 - 4
2
So with the given expression of x + x - z and the given values of x = 3 and z = 4, the expression should sum to: 2
