What is the question?
Answer:
a=12
Step-by-step explanation:
If you solve for x, you divide by (a-12) to isolate x on the left side:
x = (a+8)/(a-12)
If the numerator is 0 you will be dividing by zero, which invalidates the solution. This will happen for a=12.
I'm pretty sure it's A since B,C,and D wouldn't make sense.
