When you use this:(4,0);m=1

Question

and write it in point-slope form, does it become y=(x-4)?

Answer 1

yes it does.
With (x1,y1) = (4,0) and m = 1

The equation for a line is
y - y1 = m(x - x1)
y - 0 = 1(x - 4)

y = x - 4

So, yes you are right. Well done!