Question 1036784
A line perpendicular to the given line would be like  {{{5x-2y=c}}}.  Use the required and given point to find c.   Solve the equation for y in terms of x and put into general form.



{{{ax+by=c}}}-----standard form
{{{by=-ax+c}}}
{{{y=(-ax+c)/b}}}
{{{y=-(a/b)x+c/b}}}-----general form or slope-intercept form



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That shows slope is  {{{-(a/b)}}} for a standard form linear equation of {{{ax+by=c}}}.