Perpendicular Graphing #20

Question

Write the equation of the line perpendicular to y= -2 that passes through (5, -3).

Answer 1

y = -2 is a horizontal line, so any line perpendicular to it must be a vertical line, which has an equation of the form

 

x = constant.

 

If it passes through (5,-3) then x = 5 and the equation of the line is just

 

x = 5.

Answer 2

y = -2 is a straight horizontal lines passing through -2 on the y-axis.  (slope = 0)

 

Perpendicular to a horizontal line means your new line will be vertical (slope undefined). Since it must pass through (5,-3), the desired equation is x = -3.