Question

(+4)4.Expand37 + 8 + 9 + 10 +117 + 8 + 9 + 10 +11 + 12 + 133 + 4 + 5 + 6 + 7O7 + 11 + 15 + 19 +23

Answer 1

In the summation, we have n equals 3 and upto 7.

To expand the summation, substitute the value of n in the function from 3 to 7,

`(3+4)=7`
`(4+4)=8`
`(5+4)=9`
`(6+4)=10`
`(7+4)=11`

Thus the expansion is

`7+8+9+10+11`

The correct option is a.