Question

WHICH OF THE FOLLOWING TERMS OF THE A.P 84, 80, 76, 72 ... WILL BE FIRST NEGATIVE TERM?

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Answer:

First negative term in given A.P = 23 rd term

Step-by-step explanation:

Given A.P: 84,80,76,72,...

First term (a) = 84,

$common\: difference (d)=a_{2}-a_{1}\\=80-84\\=-4$

$We \: know \: that ,\\\boxed{n^{th}\: term =a_{n}=a+(n-1)d}$

We have to find when the first negative term appear in the A.P.

$a_{n}<0$

$\implies 84+(n-1)(-4)<0$

$\implies 84-4n+4<0$

$\implies 88-4n<0$

$\implies -4n<-88$

$\implies n > \frac{-88}{-4}$

$\implies n>22$

Therefore,

First negative term appear at 23 rd term in A.P

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