Yes the x values are all different, if two were the same then it would not be one but in this case it is
D=vt
1680=5(p-w)
p-w=336
1680=4(p+w)
p+w=420
p-w+p+w=336+420
2p=756
p=378 mph, and since w=420-p
w=42 mph
So the plane's velocity in still air is 378 mph and the wind speed is 42mph.
Answer:
oil production: John d Rockefeller
steel manufacturing: Andrew Carnegie
Clothing: william cockerill
industrializatuon expansion: Frances Cabot Lowell
Step-by-step explanation: