Question

Which term of the A.P. 121,117,113,...is its first negative term?

Answer 1

Answer:

Tn=a+(n-1) d

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

-121=-4n+4

4n=125

4n=31.25=32

Since the value of n is a decimal number, hence 0 is not the term of given A.P

And after 0 the first negative term will come.

Hence the 32nd is the first negative term.

Answer 2

Answer:

32

Step-by-step explanation:

a=121. d= -4. an<0

an= a+(n-1)d

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

121-4n+4

0=125-4n

since an<0

125-4n<0

n>31 1/4

n=32