Question

Check whether 140 is a term of the Ap -7 -4 -1 ,2

Answer 1

Answer:

a=-7

d=3

an=140

an=a+(n-1)d

140=-7+(n-1)3

140=-7+3n-3

140=-10+3n

150=3n

n=50 hence 140 is there in AP as 50th term

Answer 2

an=140

a=-7

d=-4-(-7)

=3

an=a+(n-1) d

140=-7+(n-1) 3

140+7=(n-1) 3

147=(n-1) 3

147/3=(n-1)

49=(n-1)

49+1=n

50=n

=> 140 is the 50th term of the given A. P.