Answer:
Whenever a function is parallel to something, that means they both have the same slope. If -1 is the slope of the function that is parallel, then that means both of them have a slope of -1.
Therefor,
Plug in -1 into y=mx+b --> y= -x + b
Now plug in our point (-1,4) to find b:
4 = -(-1) + b
4 = 1 + b
3 = b
This means the answer is:
y= -x + 3