Move all terms containing p to the left side of the equation.
Subtract 3p from both sides of the equation.
Subtract 3p from -6p.
Move all terms not containing p to the right side of the equation.
Add 21 to both sides of the equation.
Add -12 and 21.
Divide each term by -9 and simplify.
Divide each term in -9p=9 by -9.
Cancel the common factor of -9.
Cancel the common factor.
Divide p by 1.
Divide 9 by -9.
Solve for p -6p-21=3p-12