Question 57851
decide whether lnes p1 and p2 are perpendicular:

line p1:y= {{{highlight(3)}}}x + 5
line p2: y= {{{highlight(1/3)}}}x + 5
Perpendicular lines have slopes that are negative reciprocals of each other (opposite signs and upside down).
The slope intercept form of a line is {{{highlight(y=mx+b)}}}, where m is the slope and (0,b) is the y-intercept.
:
p1 has a slope of, m=3
p2 has a slope of, m=1/3
:
They are upsides down form each other, but they are NOT opposite signs from each other, therefore they are NOT perpendicular.
Graphically, here's what they look like.  They are not intersecting at right angles:
{{{graph(300,200,-15,15,-10,10,3x+5,(1/3)x+5)}}}
Happy Calculating!!!