A point on the graph (for train b) that is exact is (2,250). From the origin, the rise is 250 and the run is 2. Rise/run would give us 250/2, which is 125. This means that train B travels 125mi every hour. For train A, we subtract the distance from hour 2 from hour 3 to get the miles per hour (because 3-2=1, subtracting the distance of hour 3 from 2 will give us the distance in 1 hour). 180-120= 60, meaning train A travels at 60mph. 60<125, meaning A
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Find the slope m.
m = (1 - 2)/(3 - (-1))
m = -1/(3 + 1)
m = -1/4
Use the slope and one of the points and plug into the point-slope formula.
y - 1 = (-1/4)(x - 3)
Isolate y.
y - 1 = (-1/4)x + (3/4)
y = (-1/4)x + (3/4) + 1
y = (-1/4)x + (7/4)
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Hello, please consider the following.

Let me know if you need further explanation.
Thank you