Question

find the sum of last ten terms of the ap -5,-7,-9........-51.

Answer 1

Step-by-step explanation:

$a = - 5 \\ d = - 7 - ( - 5) \\ - 7 + 5 = - 2 \\ n = 4\\ an = a + (n - 1) \times d \\ an = - 5 + (4 - 1) \times ( - 2) \\ - 5 + 3 \times ( - 2) \\ - 5 + ( - 6) \\ - 5 - 6 \\ - 11$

$A = - 5 \\ d = - 2 \\ n = 5 \\ an = a + (n - 1) \times d \\ = - 5 + (5 - 1) \times (- 2) \\ = - 5 + 4 \times ( - 2) \\ = - 5 + ( - 8) \\ = - 5 - 8 \\ - 13$

$a = - 5 \\ n = 6\\ d - 2\\ an = a + (n - 1) \times d \\ = - 5 + (6 - 1) \times ( - 2) \\ = - 5 + 5 \times ( - 2) \\ - 5 + ( - 10) \\ - 5 - 10 \\ - 15$

you can find all terms like this