SOLUTION: Find the value of k such that the graphs of x + 7y = 70 and y + 3 = kx are perpendicular.

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Question 287756: Find the value of k such that the graphs of x + 7y = 70 and y + 3 = kx are perpendicular.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find the value of k such that the graphs of x + 7y = 70 and y + 3 = kx are perpendicular.
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Solve each equation for "y":
y = (-1/7)x + 10
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y = kx - 3
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If the 2nd equation is perpendicular to the 1st,
(-1/7)k = -1
(1/7)k = 1
k = 7
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Cheers,
Stan H.