Question

give me answer plzz​

Answer 1

Answer:

S10 = 0

Step-by-step explanation:

a12 = -13

=>    a + 11d = -13  ---> (1)

S4 = 24

(4 / 2)(2a + (4 - 1)d) = 24

2(2a + 3d) = 24

2a + 3d = 12  ---> (2)

Multiplying (1) with 2 on both sides and Subtracting (2) from (1),

(1) x 2 =>  2a + 22d = -26

(2)      =>  2a + 3d    =   12

            (-)      (-)         (-)

--------------------------------------

                    19d = -38       =>      d = -2

Substituting 'd' value in (1),

a + 11(-2) = -13

a - 22 = -13

a = -13 + 22   =>   a = 9

Therefore, sum of first ten terms is

S10 = (10 / 2)(2(9) + (10 - 1)(-2))

      = 5 (18 -2(9))

      = 5 (18 - 18)

S10 = 0

Hope it is useful...  And sorry if there is any inconvenience in my typing...