X axis: keep x value, change the sign of the y value
Y axis: keep y value, change the sign of the x value
He would change his tires a total of 4 times.
You divide the numbers like so:
160,000/40,000=4
6/7-2/3
Make sure they have the same denominators which means looking for the GCF
So the GCF is 21 in this case
6/7= 18/21
2/3= 14/21
18/21 - 14/21= 4/21
The answer is 4/21