Question

Which term of the AP 121,117,113 is the first negative term​

Answer 1

Answer:32nd term

Step-by-step explanation:

a=121

d=-4

Required to find=first term less than zero,in essence-first negative term.

So the equation to get the value of n for first negative term must be written as:-

a+(n-1)d<0

or,121+(n-1)-4<0

or,125-4n<0

or,4n>125

n>31.25

n must be greater than 31.25 and be a whole number,which is 32.

Hence the 32nd term of the AP will be the first negative term.

Answer 2

Answer:

Step-by-step explanation: let the nth term of the given AP be negative, that is

$t_{n}$<0

Here a = 121, d = 117 - 121 = -4

So,

121 + (n - 1)(-4)<0

121 - 4n + 4<0

4n > 125

n >31.25

This means that 32th term will be negative.