I'll be quick with this one. This website might possibly help you determining on what type of answer you need. Trust me, this site is golden :).
Sorry, if I couldn't respond with my own question.
https://quizlet.com/105691084/continental-margins-ocean-provinces-flash-cards/
Economic growth and development
Fertile soil and mild climate!
The answer should be 3a-6+14 = 3a+8.