would you be able to answer this engineering economic question quickly please:

1. For the cash flows, determine the number of possible ROR (i* values) by performing both Descartes rule of signs and Norstroms criterion tests.

2. Find the external rate of return using the modified rate of return (MIRR approach), at an investment rate of 12% per year, and a borrowing rate of 10%.

(Hint: Finding approximate i* value from factor tables is fine. You can just show i* is between which two values)

Year	0	1	2	3	4
NCF	-4000	2000	5000	-9000	7000