First, find out the y-intercept(s).
For 5, it is 6. For 6, it is 150. For 7, it is 20. For 8, it is 0.
Now we need to find the slopes.
For 5, it goes down one and right 2, so it would be -1/2 (rise/run).
For 6, it goes up 100 and right 2, so it would be 100/2 (rise/run) or 50.
For 7, it goes up 10 and right 3, so it would be 10/3 (rise/run).
For 8, it goes up 25 and right 1, so it would be 25/1 (rise/run) or 25.
Then you plug into the equation: y = mx + b
5: y = -1/2x + 6.
6: y = 50x + 150.
7: y = 10/3 + 20.
8: y = 25x + 0 which would be y = 25x (since add 0 is useless).
