I have two left I need help with and don't understand.
Find the partial sum S6
1. An=3n+2
2. Find the number of terms n in an arithmetic sequence if a1=20, d=5, and An=75.
Find the partial sum S6
1. An=3n+2
2. Find the number of terms n in an arithmetic sequence if a1=20, d=5, and An=75.