Answer
Please see the chart.
The differences represent how much gas is supplied by the rest of the world (not including the United States).
Work Step by Step
Total Supply:
$y=-16x^2+150x+8945$
$x=0$
$y=-16x^2+150x+8945$
$y=-16*0^2+150*0+8945$
$y=8945$
$x=1$
$y=-16*1^2+150*1+8945$
$y=-16+150+8945$
$y=134+8945$
$y=9079$
$x=2$
$y=-16*2^2+150*2+8945$
$y=-64+300+8945$
$y=9181$
$x=3$
$y=-16*3^2+150*3+8945$
$y=-144+450+8945$
$y=9251$
$x=4$
$y=-16*4^2+150*4+8945$
$y=-16*16+600+8945$
$y=-256+9545$
$y=9289$
Domestic Supply
$y=8x^2+80x+8443$
$x=0$
$y=8x^2+80x+8443$
$y=8*0^2+80*0+8443$
$y=8443$
$x=1$
$y=8x^2+80x+8443$
$y=8*1^2+80*1+8443$
$y=8+80+8443$
$y=8531$
$x=2$
$y=8x^2+80x+8443$
$y=8*2^2+80*2+8443$
$y=32+160+8443$
$y=8635$
$x=3$
$y=8x^2+80x+8443$
$y=8*3^2+80*3+8443$
$y=72+240+8443$
$y=8755$
$x=4$
$y=8x^2+80x+8443$
$y=8*4^2+80*4+8443$
$y=16*8+320+8443$
$y=144+8763$
$y=8907$
Differences:
$8945-8443=502$
$9079-8531=548$
$9181-8635=546$
$9251-8755=496$
$9289-8907=382$
