i need help with this plss

Answer:
6m - 15 = 9m+9
Step-by-step explanation:
Looking at option b;
6m - 15 = 9m+9
Collect the like terms
6m-9m= 9 + 15
-3m = 24
Divide both sides by -3
-3m/-3 = 24/-3
m = -8
Hence the equation that has -8 as solution is 6m - 15 = 9m+9