SOLUTION: Determine whether the lines are parallel, perpendicular or neither. y = 1/6x - 20 y = 6x + 15 and y = 7x - 12 y = 7x + 15 and y = -1/9x + 14 y = 9x + 16 My answer

Algebra ->  Algebra  -> Coordinate-system -> SOLUTION: Determine whether the lines are parallel, perpendicular or neither. y = 1/6x - 20 y = 6x + 15 and y = 7x - 12 y = 7x + 15 and y = -1/9x + 14 y = 9x + 16 My answer       Log On

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Question 108103: Determine whether the lines are parallel, perpendicular or neither.
y = 1/6x - 20
y = 6x + 15
and y = 7x - 12
y = 7x + 15
and y = -1/9x + 14
y = 9x + 16 My answer is Perpendicular to the 1st and 3rd question and the 2nd question is parallel. I am sure how I know that - can you explain this - I don't know where to start.

Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
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).