Answer :
7x=3x+12
move the x to one side of the equation (subtract 3x from each side of the equation)
4x=12
get x alone (divide each side of the equation by 4)
x=3
move the x to one side of the equation (subtract 3x from each side of the equation)
4x=12
get x alone (divide each side of the equation by 4)
x=3