<PRE><B>Question 1136512</B>
slopes are needed
for line 1 it is -26-(-10) divided by 0-8, and that is -16/-8 or 2
for line 2 it is 4-5 divided by 4-2 and that is -1/2
2 and -1/2 are negative reciprocals of one another.  The lines are perpendicular

y+26=2x
y=2x-26
y-4=(-1/2)(x-4)
y=(-1/2)x+6
{{{graph(300,300,-30,30,-30,30,2x-26,(-1/2)x+6)}}}</PRE>