Question

The 6th term of an AP is -10 & it's 10th term is -26 . Determine the 15th term of the AP?
​

Answer 1

Step-by-step explanation:

tn=a+(n-1)d

t-10=a+5d

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

a+9d=-26-----2

2-1

4d= -16

d= -4

sub d = -4 in 1

a-20= -10

a= 10

t15=10+14(-4)

=10-56

= -46

Answer 2

Answer:

6th term of AP = -10

⇒ a + (n-1)d = -10

a + (6-1)d = -10

a + 5d = -10

a = -10 - 5d — (i)

10th term of AP = -26

⇒ a + (n-1)d = -26

a + (10-1)d = -26

a + 9d = -26

a = -26 - 9d — (i)

Now we compare both the equations:-

Since we know that both the values stand for ‘a’, we can say that they are equal to each other.

-10 - 5d = -26 - 9d

-5d + 9d = -26 + 10

4d = -16

d = -4

Now we find the value of ‘a’ by substituting the value of ‘d’ in equation (i):-

a = -10 - 5d

a = -10 -5(-4)

a = -10 + 20

a = 10

Now we find the value of the 15th term:-

Formula = a + (n-1)d

10 + (15-1)-4

10 + (14)-4

10 + (-56)

10 - 56

-46 Ans

15th term of AP = -46

Hope it helps

Please mark my answer as BRAINLIEST