Question

X+1 , 2x+3 and X+7 are the second, third and fourth terms of an arithmetic series. Find the value of X and hence calculate the common difference.​

Answer 1

x = 1,

Common Difference = -3

Explanation:

Each number in series has the same difference, hence

1. (x + 1) - (2x+3) = (2x + 3) - (x + 7) Solve to find => x = 1
2. Plug in value of x into (x+1) - (2x+3)

Which solves for -3

Answer 2

x=1

c.d.=3

Explanation:

2(2x+3)=x+1+x+7

4x+6=2x+8

4x-2x=8-6

2x=2

x=1

so terms are 2,5,8

c.d.=5-2=3