Step-by-step explanation:
A has no solution.
15x - 45 = 15x + 75
-45 = 75
is false for every value of x.
in other words, when you add to the same thing different amounts, the result cannot be identical ever.
B has a solution
-45x - 45 = -75x + 75
-120x = 120
-x = 1
x = -1
C has a solution
45x - 45 = -15x + 75
60x = 120
x = 2
D has a solution
15x - 45 = 75x + 75
-120 = 60x
-2 = x
