9x + 4y = -39 3x + y = -9 a. x = 5, y = -21 b. x = 1, y = -12 c. x = 12, y = -45 d. x = -12, y = 1

How do you find principle and simple interest

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.

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?