Which equation has solution x = -3?

a) 2x - 7 = -1
b) 3x + 8 = 1
c) 1/2 x + 8 = 10
d) 1/2 (2x - 6) = -6

A) 2(-3) - 7 = -1          B) 3(-3) + 8 = 1          
       -6 - 7 = -1                  -9 + 8 = 1
         -13 = -1                        -1 = 1

C) 1/2(-3) + 8 = 10          D) 1/2 (2(-3) - 6) = -6
     -1.5 + 8 = 10                      1/2 ( -12) = -6
       6.5 = 10                                -6 = -6

D is the answer

If you put x = -3 in these options, only option D gets the required answer. So option D is correct.