That's point-slope form:
y - y1 = m(x - x1)
Where y1 is the y-value of a point on the line, x1 is the x-value, and 'm' is the slope.
So let's find out what goes in the first blank.
As we can see, they replaced 'x1' with -1, and one of our points have an x-value of -1, that point is (-1, -2), this means y2 must be -2:
y + 2 = m(x + 1)
Now let's find the slope between the two points.
m = y2-y1/x2-x1
m = (10+2)/(3+1)
m = 12/4
m = 3
So the slope is 3, plug that in:
y + 2 = 3(x + 1)
