With steps please.

According to the Descartes' rule, the number of positive i* value for the following cash flow is (lsas 3) Year 0 1 2 3 4 5 6 Revenue, $ 0 9,000 20,000 22,000 30,000 36,000 40,000 35,000 12,000 15,000 23,000 25,000 25,000 25,000 Cost, $ 30 10 20 O DLL