Here is a graph. When you use a graphing calculator, it isn't always necessary to solve for y.
Note different colors are used for the different problems. Problem 2 has a dashed line, as described by "Remember, ...".
Answer:
Step-by-step explanation:
let the speed of one plane=x
speed of other plane=x+80
time=4 hrs
then 4x+4(x+80)=3800
4x+4x+320=3800
8x=3800-320
or 8x=3480
x=435
speed of one plane=435 m/h
speed of other plane=435+80=515 m/h
2.
Let he walks x hrs
then he take a taxi for 2-x hrs
4x+(2-x)50=31
4x+100-50x=31
-46x=-69
so he walks 3/2 hrs=1.5 hrs
travels by taxi=2-1.5=0.5 hrs
distance traveled by taxi=0.5×50=25 miles
9 is in the hundred thousands place, 8 is in the ten thousands place, 7 is in the thousands place, 1 is in the hundreds place, 6 is in the tens place, 4 is in the ones place.
