Which is the answer ?! Please help

Ab and bc form a right angle at point b. if a= (-3,-1) and b= (4,4) what is the equation of bc?

Proving the parallelogram diagonal theoremgiven abcd is a parralelogam, diagnals ac and bd intersect at eprove ae is conruent to ce and be is congruent to de

Abox holds 500 paperclips. after a week on the teacher's desk 239 paperclips remained. how many paperclips were used?