SOLUTION: through (6, -9), perpendicular to 7x -8y = -30

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Question 1176126: through (6, -9), perpendicular to 7x -8y = -30
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

y=mx%2Bb
passes through (6, -9)
and perpendicular to 7x+-8y+=+-30

perpendicular lines have slopes negative reciprocal to each other
so find a slope of given line
7x+-8y+=+-30...solve for y
7x+%2B30+=8y+
%287%2F8%29x+%2B30%2F8+=y+
y=%287%2F8%29x+%2B15%2F4++-> slope is %287%2F8%29
perpendicular line will have a slope -1%2F%287%2F8%29=-8%2F7

so far, equation is

y=-%288%2F7%29x%2Bb
use given point (6, -9) to calculate b


-9=-%288%2F7%296%2Bb
-9=-%2848%2F7%29%2Bb
-9%2B48%2F7=b
-63%2F7%2B48%2F7=b
b=-15%2F7
and your equation is
y=-%288%2F7%29x-15%2F7