Question 66081
Hi Brighid,
Determine which two equations represent perpendicular lines:
a)y=5/3x-4
{{{highlight(b)}}}y=4x-5/3
{{{highlight(c)}}}y=-1/4x+5/3
d)y=1/4x-5/3
This is how you know.  Perpendicular lines have slopes that are negative reciprocals.  (opposite signs and upside down)
The slope intercept form of a line is: {{{highlight(y=mx+b)}}}, where the slope is m and (0,b)=y-intercept.
(b) has a slope of m=4=4/1
(c) has a slope of m=-1/4
The slopes have the opposite signs and are upside down form each other.
Happy Calculating!!!