Question

Trying to finish this test at 3:30 am plz help

Answer 1

Given:

The given sum is:

`\sum _(k=4)^9(5k+3)`

To find:

The expanded form and find the sum.

Solution:

We have,

`\sum _(k=4)^9(5k+3)`

The expanded form of given sum is:

`\sum _(k=4)^9(5k+3)=(5(4)+3)+(5(5)+3)+(5(6)+3)+(5(7)+3)+(5(8)+3)+(5(9)+3)`

`\sum _(k=4)^9(5k+3)=(20+3)+(25+3)+(30+3)+(35+3)+(4+3)+(45+3)`

`\sum _(k=4)^9(5k+3)=23+28+33+38+43+48`

`\sum _(k=4)^9(5k+3)=213`

Therefore, the correct option is C.