What is 18=j+4 plz help

Liz is shipping a package to her friend.the maximum weight of a medium flat-rate box is 20 pounds,including the box which weighs 6 ounces.write and solve an inequality to describe the possible weight ,w, of the contents that liz will ship to her friend if she must use a medium flat-rate box.

What is the value of x in the following equation. -x ^3/2 = -27

Two years ago a man was six times as old as his daughter. in 18 years he will be twice as old as his daughter. determine their present ages.