Question 681702
Starting with 8x-7y=77
Isolate y
8x-7y=77
8x-7y+7y = 77+7y
8x=77+7y
8x - 77 = 77 + 7y - 77
8x - 77 = 7y
...
7y = 8x - 77
y = {{{(8/7)x-11}}}
...
The slope is {{{8/7}}}
A perpendicular line will have a negative inverse/reciprocal slope of {{{-7/8}}}
...
Using point(7,-12)
y--12 = {{{-7/8}}}(x-7)
y+12 = {{{(-7/8)x-(7/8)(-7)}}}
y = {{{(-7/8)x + 49/8 - 12}}}
y = {{{(-7/8)x + 49/8 - 12(8/8)}}}
y = {{{(-7/8)x + 49/8 - 96/8}}}
{{{highlight_green(y = (-7/8)x - 47/8)}}}

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