Question

find the value of x for which (8x+4), (6x-2)and (2x+7)are in ap

Answer 1

lets say  first term a1 = 8x + 4 , second term a2 = 6x -2 and a3 = 2x + 7

since a1 , a2 , a3 are in a p

then a2 - a1 = a3 - a2      [ common difference of A.P ]

⇒ (6x -2) - ( 8x + 4) = ( 2x + 7 ) - (6x - 2)

⇒ 2(6x -2) -8x -4 = 2x +7

⇒12x - 4 - 8x - 4 = 2x + 7

⇒2x = 7+8

⇒ x = 15/2