Question

The 59th and 4th team of an Ap are - 61 and 64 respectively. Show that the common differences is - 2.5 and 23rd term is 16.5​

Answer 1

See answers below

Explanation:

T59 = a+58d = -61

T4 = a+3d = 64.

Subtract

58d-3d = -61-64

-55d = -125

d =125/55

d = 25/11

Get a;

From 2

a+3d = 64

a+3(25/11) = 64

a = 64-75/11

a = 704-75/11

a = 629/11

T23 = a+22d

T23 = 629/11+22(25/11)

T23 = 1179/11