First find slope....
slope=m=(y2-y1)/(x2-x1)
m=(-6-3)/(-6-3)
m=-9/-9
m=1
Point slope form is y-y1=m(x-x1) where m=slope and (x1,y1) is any point on the line so using m=1 and (3,3) we have:
y-3=x-3 but the standard form is ax+by=c so we need to solve for the constant...
y-3=x-3 subtract x from both sides
y-x-3=-3 add 3 to both sides
y-x=0 and x should have a positive coefficient...divide both sides by -1
x-y=0
