Slobs, can you answer my question when you're done?
Answer:
slope of AB = Y2 -Y1/X2 -X1
=7 - 3/-5-(-5)
=4/-5 +5 = 4/0
= undefined ( a number divided by 0 is undefined)
slope of CD =9 -9/-10-1
= 0/-11
= 0
since AB is not equal to CD
THE LINES ARE PERPENDICULAR
36
Why? 3 x 1=3
108/3=36
36 x 3=108
Hope it helps