Algebra1
posted by Need Help .
find the slope, if it exists, for the line containing the pair of points
(15.2,5.6) and (13.2, 4.5)
slope m= ?

The long way of doing this is as follows:
y = mx + b
5.6 = 15.2m + b
4.5 = 13.2m + b
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Two equations, two unknowns. Subtract equation 2 from #1 and solve for m.
I get 0.55 but check my work.
The short way is
(y1y2)/(x2x2) = ??