Question

which term of the Ap :121,117,113......is its first negative term

Answer 1

It will be not in Ap

Answer 2

a = 121 d = -4

a + (n-1)d > 0

121 + (n - 1)-4 > 0

n - 1 < 121/4

n-1 < 30.25

n < 31.25

so, upto 31st term it is positive

⇒ 32 nd term is first negative term

a₃₂ = a + 31d

= 121 + 31 (-4)

= 121 - 124

= 1