Question 890188
1.  let x be the number, then
x +2x = 18
3x + 18
x = 6
2.  let x be the number
8x = x +35
7x = 35
x = 5
3.  let x be the number
3(x+13) = 7x - 9
3x +39 = 7x -9
4x = 48
x = 12