please explain how to solve this in details. It would be great if you could include the diagram of time

A small business borrows $ 12,000 at a nominal interest rate of 12% compounded quarterly, to help finance start-up costs. A $ 750 payment is made at the end of every 6 months during the time it takes to repay the loan. Three months before the 9th payment is due, the company refinances the loan with a nominal interest rate of 9%, compounded monthly. Under thisscheme refinancing, a payment of R must be made monthly, with the first monthly payment starting when it should have been the 9th payment based on the old loan. In total there are 30 monthly payments that will fully pay off the loan. Determine the value R