Question

HELP PLEASE EXPLAIN HOW TO EVALUATE

Answer 1

• n=[3,8]

So

`\\ \rm\Rrightarrow \sum^8_(n=3)5n`

`\\ \rm\Rrightarrow 5(3)+5(4)+5(5)+5(6)+5(7)+5(8)`

`\\ \rm\Rrightarrow 15+20+25+30+35+40`

`\\ \rm\Rrightarrow 165`

Answer 2

165

Explanation:

The symbol
`\sum` is used to denote a sum of multiple terms.

The number below
`\sum` is the first term.

The number above
`\sum` is the last term.

Each term can be determined by using the given equation.

`\begin{aligned}\displaystyle \sum_(n=3)^(8)5n & =5(3)+5(4)+5(5)+5(6)+5(7)+5(8)\\ & = 5(3+4+5+6+7+8)\\ & =5(33)\\ & = 165\end{aligned}`