Write and solve an equation.
9. In one baseball season, Peter hit twice the difference of home runs Alice hit and 6. Altogether, they hit 18 home runs. How many home runs did each player hit that season?
10. The perimeter of a pallalelogram is 72 meters. The width of the pallalelogram is 4 meters less than its lengh. Find the length and the width of the pallalelogram.