Question

which term of ap 21,18,15.....-81 also find which term is zero

Answer 1

Heya !!


AP = 21 , 18 , 15...........


Here,



First term ( A ) = 21



Common difference ( D ) = 18-21 = -3



Tn = -81


A + ( N - 1 ) × D = -81




21 + ( N - 1 ) × -3 = -81



21 - 3N + 3 = -81





-3N = -81 - 24


-3N = -105



N = 105/3 = 35



Hence,



35 term of the given AP will be equal to -81.

Answer 2

plz refer to this attachment