Question

Is 144 a term of the AP .3,7,11 ...justify your answer.

Answer 1

a = 3

d = T2 - T1 = 7 - 3 = 4

L = 144

=> a + (n-1) d = 144

=> 3 + (n-1) 4 = 144

=> (n-1) 4 = 141

=> n - 1 = 141 / 4

=> n = 141/4 + 1

=> n = 145/4

But, number of terms can not be fractional

So 144 is not a term of the given AP

Answer 2

a=3
d=7-3=4
144=3+(n-1)×4
144-3=4n-4
141+4=4n
145/4=n
36.25=n
as term can't be in decimal point therefore it is not a term of sequence.
I hope it will help you!!!!