Question 349605
Find the slope of each line by convert to slope-intercept form, {{{y=mx+b}}}.
{{{ax+3y=9}}}
{{{3y=-ax+9}}}
{{{y=-(a/3)x+3}}}
{{{m1=-(a/3)}}}
.
.
.
{{{3x+y=-4}}}
{{{y=3x-4}}}
{{{m2=3}}}
.
.
.
Perpendicular lines have slopes that are negative reciprocals,
{{{m1*m2=-1}}}
{{{-(a/3)*3=-1}}}
{{{highlight(a=1)}}}
.
.
.
{{{graph(300,300,-10,10,-10,10,-(1/3)x+3,3x-4)}}}