Question 1208658
{{{y=mx+b}}} basic slope-intercept form


Choose one of the points, maybe,  (-3,3).


{{{y=((5-3)/(-9-(-3)))x+b}}}

{{{y=(-2/6)x+b}}}

{{{y=-x/3+b}}}

and using the chosen point,

{{{3=-(-3)/3+b}}}

{{{3=1+b}}}

{{{b=2}}}


The equation wanted is {{{highlight(y=-x/3+2)}}}