"A construction company is making a 12-year financial calculation. According to this, it is estimated that there will be an expense of 20,000 TL at the beginning of the project, a return of 5,000 TL at the end of the first year, 7,000 TL at the end of the third year, and 9,000 TL at the end of the sixth year. If the annual compound interest rate is 8%, what is the NPV (Net Present Value) of this investment?"

(dont use software pls)