Question

How do you find the sum of `Sigma (3i-1)` from i=1 to 6?

Answer 1

57

Explanation:

`Sigma_1^6(3i-1)`
-1 is repeated 6 times
`Sigma_1^6(3i)-6`
`=3(1+2+3+4+5+6)-6`
`=3(21)-6`
`=63-6=57`