Answer:
8 = r; (9, 8)
Step-by-step explanation:
-y₁ + y₂\-x₁ + x₂ = m
-2 + r\3 + 9 = ?\12
-2 + r = 6
+2 + 2
__________
r = 8
The reason why the expression has to equal 6 is because 6⁄12 simplifies to ½, and the numerator has to be a six in order to get the rate of change [slope] of ½, so there you have it.
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