Question 108103
IN THE FIRST SET OF 3 NONE ARE PARALLEL NOR PERPENDICULAR.
SLOPES ARE: 1/6, 6 & 7 NONE EQUAL & NONE THE NEGATIVE RECIPRICAL.
IN THE SECOND SET OF 3 ONE PAIR ARE PERPENDICULAR.
HE SECOND HAS A SLOPE OF -1/9 & THE THIRD HAS A SLOPE OF 9 WHICH IS THE NEGATIVE RECIPRICAL OF 9. THEREFORE THESE 2 LINES ARE PERPENDICULAR. 
THE LINES Y=7X-12 & Y=7X+15 ARE PARALLEL LINES BECAUSE THEY HAVE THE SAME SLOPE OF (7).