According to Descartes' rule of signs, how many possible * values are there for the cash flows shown?(a) Find the external rate of return using the modified rate of return (MIRR approach), at an investment rate of 14% per year, and a borrowing rate of 10%. (b) Determine the external rate of return using the ROIC approach (30 point) Year 0 1 2 3 4 5 6 NCF, $ -9000 +4100 - 2000 7000 +12,000 +700 +800 According to Descartes' rule of signs, how many possible * values are there for the cash flows shown?(a) Find the external rate of return using the modified rate of return (MIRR approach), at an investment rate of 14% per year, and a borrowing rate of 10%. (b) Determine the external rate of return using the ROIC approach (30 point) Year 0 1 2 3 4 5 6 NCF, $ -9000 +4100 - 2000 7000 +12,000 +700 +800