twice the difference between x and 28 is 3 times a number
The difference between x and 28:
x - 28
Twice the difference means we multiply x - 28 by 2:
2(x - 28)
The phrase a number means an arbitrary variable, let's call it x
x
3 times a number:
3x
The word is means equal to, so we set 2(x -...