Arithmetic progression - The sum of an arithmetic series is \sum_{r = 1}^{n} (80 - 3r)

Krishna (last edited 3 years ago) (Expert, Educator @Qalaxia)

Step 1: To find the 1st term, plug in (any variable)n = 1. in the sequence and simplify

[NOTE: Knowing that, n represents the position of a term in the sequence. So change the n values.]

Step 2: To find the 2nd term, plug in n = 2. In the sequence and simplify

Step 3: Take the various n values and substitute in the sequence, till you get the required sequence.