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Writing Equations of Perpendicular Lines

Writing Equations of Perpendicular Lines 1.1 - Solution

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a
If two lines are perpendicular, the product of the lines' slopes need to be equal to -1.\text{-} 1.
m1m2=-1m_1\cdot m_2 = \text{-}1
9(-0.1)=?-1{\color{#0000FF}{9}}\cdot ({\color{#009600}{\text{-} 0.1}}) \stackrel{?}{=} \text{-}1
-0.9-1\text{-} 0.9 \neq \text{-}1
The lines are not perpendicular.
b
Let's follow the same procedure, test if m1m2=-1m_1\cdot m_2=\text{-} 1.
m1m2=-1m_1\cdot m_2 = \text{-}1
0.125(-8)=?-1{\color{#0000FF}{0.125}}\cdot ({\color{#009600}{\text{-} 8}}) \stackrel{?}{=} \text{-}1
-1=-1\text{-}1 = \text{-} 1
These lines are perpendicular.