Question

If x+1 , 4x and 5x+2 are in AP then x is _______. *​

Answer 1

Answer:

10 x this is answer not sure

Answer 2

Answer:

x = 3/2

Step-by-step explanation:

Let

a1 = x+1

a2 = 4x

common difference (d) = 4x - (x+1) => 4x - x -1 = 3x - 1

d = 3x - 1

n = 3

Sn = (x+1)+(4x)+(5x+2) = 10x + 3

then

Sn = n/2 [2a + (n - 1)d ]

10x + 3 = 3/2 [2(x+1) + (3 - 1)(3x - 1)]

10x + 3 = 3/2 [2x + 2 + 6x - 2]

10x + 3 = 3x + 3 + 9x - 3

10x - 3x - 9x = 3 - 3 - 3

-2x = - 3

by multiplying with (-1) on both sides we get

2x = 3

x = 3/2