the numbers are 6 and 13
let x be one of the numbers then the other is 2x + 1
their sum increased by 7 = 26
x + 2x + 1 + 7 = 26
3x + 8 = 26
subtract 8 from both sides
3x = 26 - 8 = 18
divide both sides by 3
x =
= 6
the numbers are 6 and (2 × 6) + 1 = 12 + 1 = 13