the expression -5t2+40t predicts the height, in meters, of an object t seconds after a person launches it into the air. using this expression, how many seconds will it take the object to hit the ground?

Iwill give brainliest. suppose tommy walks from his home at (0, 0) to the mall at (0, 5), and then walks to a movie theater at (6, 5). after leaving the theater tommy walks to the store at (6, 0) before returning home. if each grid square represents one block, how many blocks does he walk?