Question

If 6th term of an ap is -10 &10th term of an ap is -26 then,find the 15th term of an ap.

Answer 1

Step-by-step explanation:

a6=-10

a+5d=-10 ------(1)

a10=-16

a+9d=-16 --------(2)=

subtracting 1 from 2 ,we get

a+9d=-16

a+5d=-10

- - +

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

× 4d= -16

d=-16/4

= -4

putting the value of d in 1

a+5d = -10

a+5(-4)=-10

a-20=-10

a=20-10

a=10

now,

a15=a+14d

10+14(-4)

10-56

-46 answer

Answer 2

Answer:

6th term of AP = -10

⇒ a + (6-1)d = -10

a + 5d = -10 — (i)

10th term of AP = -26

⇒ a + (10-1)d = -26

a + 9d = -26 — (ii)  

Now, we compare equations (i) and (ii) using Elimination Method:-

a + 5d = -10

a + 9d = -26

-4d = 16 (after subtracation)

d = -4

Now, we find the value of ‘a’ by substituting value of d:-

a + 5d = -10

a + 5(-4) = -10

a + (-20) = -10

a = -10 + 20

a = 10

TO FIND:-

The value of 15th term of this AP

FORMULA:-

a + (n-1)d where ‘n’ is 15

METHOD:-

a + (n-1)d

10 + (15-1)-4

10 + (14)-4

10 + (-56)

10 - 56

-46 Ans

Hope it helps

Please mark my answer as BRAINLIEST