Your idea is right, but you can't get the principal every year. This topic does not define what is the repayment principal, so it is not what you think, "the annual repayment amount MINUS last year's interest is the repayment principal of that year", and it has nothing to do with the repayment principal. I hope you will think it over again.

The positive solution is as follows:

Solution: (1) If the loan is given to China Construction Bank and the annual repayment is X yuan, then a * * * repayment 10X, a * * * repayment is equal to the principal plus interest, then there is it.

10X = 10+ 10X 5%+( 10-X)5%+( 10-2X)5%+( 10-3X)5%+……+( 10-9X)5%

The solution is x≈ 12245 (yuan).

On the left side of the equation is the total amount to be repaid.

The first item on the right is the principal, the second item is the interest generated in the first year and the third item is the interest generated in the second year. .......