y = -2x
The formula for this would be y=mx+b. 'm' being the slope and 'b' being the the y-intercept.
The point on the line that intercepts with the y axis is (0,0) so, we wouldn't put a number for b, just remove it.
The slope formula is y2-y1/x2-x1.
point 1: (-2,4)
point 2: (2,-4)
-4-4/2+2
-8/4
-2
m = -2
Now, plug in everything we know into the formula.
y = -2x
And there you have it!
Hope this helps!
Let me know if there are any more questions you need help with :)