Adding 6 to triple a number gives 21

What situation is an example of an observational study

1. a parachutist is 800 feet above the ground when she opens her parachute. she then falls at a constant rate of 5 feet per second. select the equation that represents this situation. h = -800t + 5 y = -5x + 800 h = 5t - 800 y = 800x + 5 i need

Find the value of x for which line a is parallel to line b