What is negative 20 plus negative 15

What is x3+3x2−16x−48 divided by x−1?

You're locked out of your house. the only open window is on the second floor, 25 feet above the ground. there are bushes along the edge of the house, so you will need to place the ladder 10 feet from the house. what length ladder do you need to reach the window?

Factor the polynomial by its greatest common monomial factor.