4 kilometres is 4000 meters
4000 meters - 3400 meters = 600 meters
and as John is the one that rode 4 kilometres he rode further and by 600 meters
You could get two different functions out of this:
<u>2x + 2y = 8</u>
1). <u> 'y' as a function of 'x'</u>
Subtract 2x from each side: 2y = -2x + 8
Divide each side by 2 : <em> y = -x + 4</em>
2). <u> 'x' as a function of 'y' :</u>
Subtract 2y from each side: 2x = -2y + 8
Divide each side by 2 : <em> x = -y + 4</em>
Those two functions look the same, but that's just because the original
equation given in the problem was so symmetrical. In general, they're
not the same function.