12 + 12 = 0 since your getting rid of the constants and 12 + 7 = 19 so x = 19
Use the opposite operation in which its formed in
For example 3x = 18
you would have to multiply 3 by x right? So the opposite operation of that is divide by 3 since you dont know the value of x so do the known value which is the number 3 once you divide 18 by 3 you get 6 so put 6 on the right side and keep the equal sign between them to get x = 19.
