Question

In AP if the 12 term is -13 and the sum of 4 term is 24 what is the sum of 1st 10th term​

Answer 1

Answer:

12th term = a + 11d = -13.......... (i)

sn = n/2(2a + (n-1) d

24 = 4/2(2×a + (n-1)d)

24= 2(2a+dn- d)

2a+(n-1) d = 24/2

2a + ( n- 1) d = 12

2a + 3d=12..............(ii)

multiplying (i) by 2,

we get

2a+22d=-26..........(iii)

subtracting (iii) from (ii)

we get

-19d=38

d = -2

substituting d = -2 in (i),

a+11×-2=-13

a-22=-13

a=22-13

a=9

sn = n/2(2a+(n-1) d

s10= 5(18+9×-2)

s10=5×0

therefore

s10=0...

Answer 2

I'll do question in hurry....

hope this helps uh...

Step-by-step explanation

S 10 =10/2(2(9)+(10-1) -2

S 10 = 5(18+ (-18)

S 10 =5 (0)

S 10 =0

sum of the 10 terms is 0