Question

I'm lazy and dont feel like doing math myself. So pls help me!

I'm asking this again cuz no one answer it the first time T-T

Answer 1

55

Explanation:

Well you just plug in 10 as n.. and you get the equation:

`(10(10+1))/(2) \\(10(11))/(2)\\\\(110)/(2)\\\\55`