Hello guys let's we have an syntax and related values let's see how this works. Evaluate the given syntax 
z = ++x + y-- - ++y - x-- - x-- - ++y - x--
where x = 7 y = -3

z = ((((((++x + y--) - ++y) - x--) - x--) - ++y) - x--)
so first(++x + y--) will be evaluated
 (++x + y--)
   8 + (-3)        x=8 y = -4
 z = (((((5 - ++y) - x--) - x--) - ++y) - x--)
 (5 - ++y)
  5 - ( -3)  x=8 y = -3

 z = ((((8 - x--) - x--) - ++y) - x--)
 (8 - x--)
  8 - 8      x =7 y = -3 
 z = (((0- x--) - ++y) - x--)
 (0- x--)
  0 - 7      x =6 y = -3
 z = (((-7 - ++y) - x--)
 (-7 - ++y)
  -7 - (-2)  x = 6 y = -2
 z = (-5 - x--)
 -5 -6       x =5 y -2
 z = -11

So answer is -11