Question

what is the equation of a line with a slope of -3 that passes through the point (3,-3)?

Answer 1

We can write the equation of the line as:
\[(y-b)=m(x-a)\]
where m = the slope, and a and b are the coordinates (a,b)

Answer 2

So all that you have to do is substitute:
m = -3
a = 3
b = -3
into:
(y-b)=m(x-a)