Answer:
About $6000
Step-by-step explanation:
Multiply 689 × 9.
When you are estimating, you should round the numbers off to values that you can easily work in your head.
I would round 9 up to 10 and 689 down to 600 to compensate. Then,
10 credit hours × $600/credit hour ≈ $6000.
It should cost about $6000 to register for 9 credit hours.