What is the slope of any line perpendicular to the line passing through #(1,2)# and #(-8,1)#?

2 Answers
Harish Chandra Rajpoot
Jun 28, 2018

#-9#

Explanation:

The slope of any line perpendicular to line passing through the points #(1, 2)# & #(-8, 1)#

#=\frac{-1}{\text{slope of line passing through the points (1, 2) & (-8, 1) }}#

#=\frac{-1}{\frac{2-1}{1-(-8)}}#

#=\frac{-1}{1/9}#

#=-9#

Jim G.
Jun 28, 2018

#"perpendicular slope "=-9#

Explanation:

#"calculate the slope m using the "color(blue)"gradient formula"#

#•color(white)(x)m=(y_2-y_1)/(x_2-x_1)#

#"let "(x_1,y_1)=(1,2)" and "(x_2,y_2)=(-8,1)#

#m=(1-2)/(-8-1)=(-1)/(-9)=1/9#

#"the slope of a line perpendicular to this is"#

#•color(white)(x)m_("perpendicular")=-1/m=-1/(1/9)=-9#

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