An elevator went up 15 floors, down 9 floors, up 11 floors, and down 19 floors. find the net change.

Really need on these. i have no idea what to do

Factor x2 – 8x + 15. which pair of numbers has a product of ac and a sum of what is the factored form of the

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn. if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.