Question

in an ap, the first term is -2, the last term -29 and sum of all terms is -155. find the 11th term of this ap.

Answer 1

Answer:

a11=_32

Step-by-step explanation:

sn= _155, a=_2, an=_29

sn=n/2(a+an)

_155=n/2(_2+(_29)

_155=n/2(_2_29)

_155×2=n(_31)

_310=_31n

n=310/31

n=10

an=a+(n_1)d

_29=_2(10_1)_d

_29=_2+10d_d

_29=_2+9d

_29+2=9d

_27=9d

9d=_27

d=_27/9

d= _3

a11=a+10d

a11=_2+10(_3)

a11=_2_30

a11=_32