To find the opposite of 3x+12, find the opposite of each term.
Subtract 12 from 24 to get 12.
Use the distributive property to multiply 6 by 2x+12.
Subtract 12x from both sides.
Combine -3x and -12x to get -15x.
Subtract 12 from both sides.
Subtract 12 from 72 to get 60.
Divide both sides by -15.
Divide 60 by -15 to get -4.