Question

if the sum of 3rd and 4th term is 7 and the sum of 7th and 14th sum is -3 then find 10th term​

Answer 1

Answer:

a3=a+2d, a4=a+3d.

a7=a+6d, a14=a+13d.

Given that

a3+a4=7. a7+a14=-3.

a+2d+a+3d=7. a+6d+a+13d=-3.

2a+5d=7. 2a+19d=-3.

a+5d=7/2......(1). a+19d=-3/2......(2).

On substracting (1) from (2).

a+5d=7/2.

a+19d=-3/2.

(-) (-) (+)

-14d=10/2.

-14d=5.

d=5/-14.

d=-5/14.

From Eqn. (1).

a+5d=7/2.

a+5(-5/14)=7/2.

a-25/14)=7/2.

a=7/2+25/14.

a=98+50/28.

a=148/28.

a=74/14.

a=37/7.

an=a+(n-1)d.

a10=37/7+(10-1)(-5/14).

=37/7+(9)(-5/7).

=37/7-45/7.

=-8.

I think this is your answer.