Question 172498
{{{y=-5x+1}}}--------> This is in Slope-Intercept Form, {{{y=mx+b}}}
where --->{{{system(Slope=m[1]=-5,YIntercept=b=1)}}} --> Line 1
As wee see this line in the graph:
{{{drawing(300,300,-10,10,-10,10,graph(300,300,-10,10,-10,10,-5x+1))}}}

Now, I "think" you're looking the eqn of the line that is perpendicular to this and passing thru (2,-1)? Which is Line 2?
Remember for perpendicular lines, {{{m[2]=-1/m[1]}}}
So, {{{m[2]=-1/(-5)=1/5}}}
Then thru points (2,-1):
Via Slope-Intercept Form, {{{-1=(1/5)(2)+b}}}
{{{b=-1-(2/5)=(-5-2)/5=-7/5}}}
Therefore Line 2 -----> {{{highlight(y=(1/5)x-(7/5))}}}, Answer
We see the graph again,
{{{drawing(300,300,-10,10,-10,10,graph(300,300,-10,10,-10,10,-5x+1,(1/5)x-(7/5)))}}} ----> See GREEN Line 2, perpendicular to Line 1 (RED)
Thank you,
Jojo
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