Question

A.P question, please quick reply​

Answer 1

Step-by-step explanation:

Question:-

If the sum of 3rd a d 8th term of an AP is -30 and the sum of 7th term and 14th term is 30. Then find the tenth term.

Solution:-

Let ' a ' be the first term and ' d ' be the common difference.

Case 1:-

3rd term + 8th term = -30

→ $\rm a_{3} + a_{8} = -30$

→ a + 2d + a + 7d = -30

→ 2a + 9d = -30......(i)

Case 2:-

7th term + 14th term = 30

→ $\rm a_{7} + a_{14} = 30$

→ a + 6d + a + 13d = 30

→ 2a + 19d = 30......(ii)

Subtracting equation (i) from (ii)

→ 2a + 19d - (2a + 9d) = 30 - (-30)

→ 2a + 19d - 2a - 9d = 30 + 30

→ 10d = 60

→ d = 6

Substituting d = 6 in equation (i)

→ 2a + 9d = -30

→ 2a + 9(6) = -30

→ 2a + 54 = -30

→ 2a = -30 - 54

→ 2a = -84

→ a = -42

We have :-

• a = - 42

• d = 6

Now, we have to find the 10th term of the AP

→ $\rm a_{10}$ = a + 9d

= - 42 + 9(6)

= -42 + 54

= 12

∴ The 10th term of the AP is 12

Answer 2

thanks

hope it helps you

hope you are doing well