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The middle term in the expansion of (x/2...

The middle term in the expansion of `(x/2+2)^8` is 1120, then `x in R` is equal to a. -2 b. 3 c. `-3` d. `2`

A

`-2`

B

`3`

C

`-3`

D

`2`

Text Solution

Verified by Experts

Middle term is `(n/2+1)` th or `(4+1)^(th)` or `T_(5)`
`rArr T_(5) = .^(8)C_(4) (x/2)^(4) xx 2^(4) = 1120`
or `(8xx7xx6xx5)/(1xx2xx3xx4) x^(4) = 1120`
or `x^(4) = (1120)/(70) = 16`
or `(x^(2) + 4) (x^(2) - 4) = 0`
or `x = +- 2" "(:' x in R)`
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