Answer:
Option B: x = 15 is a solution, but x = 9 is not is the correct answer.
Explanation:
Given equation is:
x - 3 = 12
The solutions we have to check are;
x = 9 and x = 15
Putting x = 9 in the given equation;
9 - 3 = 12
6 ≠ 12
Putting x = 15 in the given equation;
15 - 3 = 12
12 = 12
Hence,
Option B: x = 15 is a solution, but x = 9 is not is the correct answer.