Explanation:
the slope of a line ("m" in the given point-slope form) is the ratio (y coordinate change / x coordinate change) when going from one point on the line to another.
we got 2 points already identified :
(-3, -4) and (1, 4).
x changes by +4 (from -3 to 1).
y changes by +8 (from -4 to 4).
the slope m is then
+8/+4 = 2
let's use e.g. (1, 4) as given point for the point-slope form (but you can use also the other, or any point on the line) :
y - 4 = 2(x - 1) = 2x - 2
y = 2x + 2
-2x + y = 2
and that is the standard form.