A superhero trying to fight crime is swinging back and forth in front of the window. At t = 3s, he is at one end of his swing and 4m from the window. At t = 7s, he is at the other end of his swing and...

A superhero trying to fight crime is swinging back and forth in front of the window. At t = 3s, he is at one end of his swing and 4m from the window. At t = 7s, he is at the other end of his swing and 20m from the window. Write an equation to model this situation.