Find three consecutive integers if twice the middle integer is equal to the sum of the first and the third

  any three consecutive integers: -5, -4, -3; or 100, 101, 102, for example

Step-by-step explanation:

If x represents the middle integer, then the first is x-1 and the third is x+1. The sum of these two is (x-1) +(x+1) = 2x, which is double the middle integer.

The desired relation is true for any three consecutive integers.

Example:

  53, 54, 55  ⇒  2(54) = 108 = 53 +55