How do i use elimination to solve the system 8x-7y=5 and 3x-5y=9 for y

What is the quadric regression equation that fits these data

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?

What is the the greatest common factor ?