Please help me this is pretty hard

Steve is scuba diving near his home in maui. at one point he is 100 feet below the surface. represent this number with a negative number. if he descends another 5 feet, what negative number will represents his.

If (x-2) 2= 49, then x could be a. -9 b. -7 c.- 2 d. 5 e.9

21 a stick 7 inches long is broken into two pieces, so that one piece is twice as long as the other one. how long are the two pieces?