If you don’t have any fractions, just subtract y from both sides.
Y=mx+b
0=mx-y+b
If you have some fractions, it’s prob easier to get rid of them before moving things around.
Ex. Y=2x+3
0=2x -y+3. It’s in Ax+By+C=0 form.
2nd Ex. Y= (1/2)x + (2/3)
Now let’s get rid of those fractions by multiplying everything by 6
6y=(6/2)x+(12/3) = 3x +4
Subtract 6y from both sides
0=3x -6y+4