6 + m = 12
A. This IS equivalent
6 + m - m = 12 - m ==> 6 = 12 - m ==> 6 + m = 12
B. This IS NOT equivalent
6 + m - 6 = 12 - 12 ==> m = 0
C. This IS equivalent
6 + m + 2 = 12 + 2 ==> 6 + m = 12
D. This IS equivalent
6 + m - 6 = 12 - 6 ==> m = 6 ==> 6 + m = 12
Answer:
B is not equivalent