Respuesta :

Answer:

add 3 to both sides of the equal sign

Step-by-step explanation:

to solve the equation you would have to add three

that is because you have to do inverse operations

and you would add because the opposite of subtracting is adding

so solving it would look like this

x - 3 = 12

  +3   +3

x = 15

this is how you check the answer:

15 - 3 = 12

    +3   +3