Explanation:
x= -2,
 (x - 5) / 2= -6
 ( (-2) - 5) / 2= -6
 (-7) / 2 = -6
 -3.5 = - 6 
right hand side not equal to left hand side of this equation.so,x= -2 cannot exist for this equation.
x=2, 
 (x - 5) / 2= -6
 (2 - 5) / 2= -6
 (-3) / 2= -6
 -1.5 = - 6
right hand side not equal to left hand side of this equation.so,x= 2 cannot exist for this equation.
x= -17
 (x - 5) / 2= -6
 ( ( -17) - 5) / 2= -6
 (- 22) / 2= -6
 -11 = -6 
right hand side not equal to left hand side of this equation.so,x= -17 cannot exist for this equation.
x= -7,
 (x - 5) / 2= -6
 ( ( -7) -5) / 2= -6
 (-12) / 2= -6
 -6= -6
right hand side equal to left hand side of this equation.so,x= -7 exist for this equation.