which term of the A.P. : 120, 116, 112,..... is first negative term?

Explanation

In the given `A.P.`,

First term, `a = 120`

Common difference `d = -4`

`:. T_n = a+(n-1)d = 120 - 4(n-1) = 124-4n`

For, `T_n` to be negative,

`124-4n lt 0`

`=> 4n gt 124 => n gt 31`

So, for `n = 32`, `T_n` will be negative.

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