SOLUTION: If the graph of the equation ax+3y=9 is perpendicular to the graph of the equation 3x+y=-4, find the value of a

Algebra ->  Rectangles -> SOLUTION: If the graph of the equation ax+3y=9 is perpendicular to the graph of the equation 3x+y=-4, find the value of a      Log On


   

Question 318876: If the graph of the equation ax+3y=9 is perpendicular to the graph of the equation 3x+y=-4, find the value of a
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Convert both equations to slope-intercept form,
ax%2B3y=9
3y=-ax%2B9
y=-%28a%2F3%29x%2B3
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3x%2By=-4
y=-3x-4
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Perpendicular lines have slopes that are negative reciprocals,
m1%2Am2=-1
-%28a%2F3%29%2A%28-3%29=-1
highlight%28a=-1%29
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