Answer:
17) 750/9 and 18) 364
Explanation:
17. Summation of 75*(0.1)^i from i=0 to infinity, that is equal to 75*(Summation of (0.1)^i). Summation of (0.1)^I is a geometric series with a sum of 1/(0.9)=10/9. Hence the series have a sum equal to 75*(10/9)=750/9
18) It's a series with sum=1+3+9+27+81+243=364