Question 322977
First you need to find the slope so use {{{m=(y2-y1)/(x2-x1)}}}

Point 1 (3,-5) is x1 and y1
Point 2 (o,-9) is x2 and y2

solve
{{{m=(y2-y1)/(x2-x1)}}}
{{{m=((-9)-(-5))/(0-3)}}}
{{{m=(-4)/-3}}} or {{{4/3}}}  is your slope.

Next use point slope formula {{{y-y1=m(x-x1)}}} to find the equation.

{{{y-(-5)=(4/3)(x-3)}}}<---- multiply using distributive property
{{{y+5=((4/3)(x))((4/3)(-3))}}}
{{{y+5=(4/3)x-4}}} 
{{{y=(4/3)x-9}}}  <----- your equation :)