How do i solve without s calculator?

You could solve it ( without a graph) in 2 easy ways :

1 use the equation that you have written in pencil and solve for y

y=3=-x+4
y=-x +1

Or you could use the point slop form after you find the y intercept y=mx+b

-3=4(-1)+b
b= 1

So the answer would be y= -x +1

Hope this help of it does feel free to give the brainliest