英文数列题目Inaparticulararichmeticprogression,thesumofthe9thand10thtermsis-64.Also
Inaparticulararichmeticprogression,thesumofthe9thand10thtermsis-64.Also,thedifferencebetweenthesumofthefirst5termsand2timesthefifthtermis-49.Whatisthesumofthefirst30terms?