Answer:
Well you could count and use the Rise/Run method, or you could use the Slope formula (x2 - x1) / (y2 - y1)
From point (0, -1) to point (1, 6) would look like this
(1 - 0) / (6 + 1) = 1/7, so your slope is 1/7
Since you already have you y-intercept (where x is 0), your whole equation would be this:
y = 1/7x - 1