It's kind of hard to read but I think I've identified three lattice points on the graph,
(-6,-3), (0,-1), (9,2)
Calculating slopes, change in y over change in x
(-1 - -3) / (0 - -6) = 1/3
(2 - -1) / (9 - 0) = 1/3
Those agree so we conclude
Answer: Slope 1/3
It's a line; it doesn't really start anywhere. Let's use the y intercept:
Answer: Starting Value: at x=0 we start at y=-1
We have a slope and a y intercept so our equation is
Answer: y = (1/3)x - 1
Check:
(1/3)(-6)-1 = -3, good
(1/3)0 - 1 = -1, good
(1/3)(9) - 1 = 2, good