Answer:
r = - 2
Explanation:
Use the slope formula to find m then equate to - 1
m =
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with (x₁, y₁ ) = (6, r) and (x₂, y₂ ) = (9, - 5)
m =
=
= - 1 ( multiply both sides by 3 )
- 5 - r = - 3 ( add 5 to both sides )
- r = 2 ( multiply both sides by - 1 )
r = - 2