Answer:
21300
Step-by-step explanation:
120∑n=13n−4
Split the summation into smaller summations that fit the summation rules.
120∑n=1 3n−4=3120∑n=1 n+120∑n=1 −4
Evaluate
3120∑n=1 n.
21780
Evaluate
120∑n=1 −4 −480
Add the results of the summations.
21780−480
Subtract 480 from 21780.
21300
