Question 1050345
Find an equation for the line that satisfies the conditions. 
1. Slope 2; passing through (4,12)
Use
y-y1 = m*(x-x1) where m = slope and (x1,y1) is the point.
y-12 = 2*(x-4)
That's it.
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2. Passing through (0,15) and (5,3)
Step 1 find the slope, m
m = diffy/diffx = (15-3)/(0-5)
m = -12/5
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Now same as #1, using either point.
y-15 = (-12/5)*(x-0)
y-15 = -12x/5
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There are only a few things to remember.
The slope, m, is obvious.  It's the change in y divided by the change in x.