Question 59332
determine whether the following pairs of lines are perpendicular or not perpendicular         
y=-x+4    
y=x-3
:
These lines are in slope intercept form {{{highlight(y=mx+b)}}}, where m=slope and (0,b)=y-intercept.
Perpendicular lines have slopes that are negative reciprocals of each other, that means they are opposite signs and upside down, because of this quality, if we multiply their slopes we get -1 {{{m*(-1/m)=-1}}}.
y=-x+4 -->> {{{y=highlight(-1)x+4}}} m=-1
y=x-3 -->> {{{y=highlight(1)x-3}}} m=1
:
If you multiply their slopes -1*1=-1, therefore the lines are perpendicular.
Happy Calculating!!!