A) Plot a point at (0, 3000), then subtract 10 for every second that passes by.
B) The slope is negative because the skydiver is falling and the graph is plotting his descent, his x intercept is at (300, 0) which means he will touch land after 300 seconds
To find the the x intercept, make y equal 0 so 0=-10x+3000, subtract by 3000 on each side, and you end up with -3000=-10x, you then divide both sides by -10 and you end up 300=x or x=300