Question

If 8,x,y,-4 are in A.P

Answer 1

In AP n-th term:

an = a + ( n - 1 ) d

where

a = first term

d = common difference

a1 = a

a2 = a + d

a3 = a + 2 d

a4 = a + 3 d

In this case:

a1 = a = 8

a4 = a + 3 d = - 4

8 + 3 d = - 4

Subtract 8 to both sides

3 d = - 12

d = - 12 / 3

d = - 4

x = a2 = a1 + d = 8 + ( - 4 ) = 8 - 4 = 4

y = a3 = a1 + 2 d = 8 + 2 ∙ ( - 4 ) = 8 - 8 = 0

x = 4 , y = 0

Your AP is:

8 , x , y , - 4

8 , 4 , 0 , - 4