Please someone help me

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

What is the equation of a line passing through (-6,5) and having a slope of 1/3

Apool measures 100 meters by 100 meters a toddler inside the pool and trows a ball 60 centimeters from one edge of the pool. how far is the ball from the opposite edge of the pool