If you are given $10 every 3.5 hours and you want to find the unit rate per hour, you want to solve for how much money you make every hour. You do this by dividing the $10 by the 3.5 hours, which will result in about $2.86 per hour. (This is a rounded value)
............................,,,;,,...............:......
The line passing through (3, -1) and (-1, 5) has this slope:
5+1
m = ---------- = -3/2
-1-3
We need to find the y-intercept. To do this, substitute the knowns (-3/2 for m, -1 for y and 3 for x) into the slope-intercept equation:
-1 = (-3/2)(3) + b. Then: -1 = -9/2 + b, and so b = 9/2 - 1 = 7/2.
The desired equation is y = (-3/2)x + 7/2.
