1. A point is moving on the graph of xy=36 When the point is at (4, 9), its x coordinate is increasing by 4 units per second. How fast is the y coordinate changing at that moment?
2. A point is moving on the graph of 4x2+9y2=36. When the point is at (3, 0), its y coordinate is decreasing by 2 units per second. How fast is its x coordinate changing at that moment?