Question 370045
{{{drawing(300,300,-10,10,-10,10,grid(1),
circle(0, -1,0.3), 
circle(2, -5,0.3), 
circle(4, -9,0.3),
graph(300,300,-10,10,-10,10,0))}}}
Use two points to determine the slope.
{{{m=(y[2]-y[1])/(x[2]-x[1])}}}
{{{m=(-9-(-1))/(4-0)=-(8/4)=-2}}}
Now use the slope-intercept form of a line,{{{y=mx+b}}}
{{{y=-2x+b}}}
Use any point to solve for {{{b}}}.
{{{-9=-2(4)+b}}}
{{{-9=-8+b}}}
{{{b=-1}}}
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{{{highlight(y=-2x-1)}}}
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{{{drawing(300,300,-10,10,-10,10,grid(1),
circle(0, -1,0.3), 
circle(2, -5,0.3), 
circle(4, -9,0.3),
graph(300,300,-10,10,-10,10,0,-2x-1))}}}