Respuesta :

Answer:

  • x + 3 = 18
  • x = 15

Step-by-step explanation:

You want an equation and solution for "the sum of a number and 3 is 18".

Number

Using x as "a number," the "sum of a number and 3" is (x +3). If that sum is 18, then we have the equation ...

  x + 3 = 18

The solution is found by subtracting 3 from both sides of the equation:

  x + 3 - 3 = 18 - 3

  x = 15

The one solution is x = 15.