im doing this one again, Mackenzie has to drive 470 miles to get home. On the way home, Mackenzie stopped to visit a client. When she started toward home, her odometer reading was 29,819, and when she got to the meeting, it was 30,001. How far does she have left to drive to get home?

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.