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The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

What is best way to getting answer for my exam is

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