Me for number 20 and 21 and also show work

Use the knowledge of x- and y- intercepts to choose the correct graph of the equation 3x+6y=6

Evaluate the following expression 1/3^2

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