Standard form (which I assume is what they want you to turn these into) is y=mx+b.
12x-5y=20 is y=2.4x-4.
Subtract 12x from both sides, -5y=-12x+20.
Multiply both sides by -1, 5y=12x-20.
Divide both sides by 5, y=2.4x-4.
y=x+4 is already in standard form- I'm not quite sure what to do.
3x+y=3 is y=-3x+3.
Subtract 3x from both sides, y=-3x+3.
x=-y+3 is y=-x+3
Ad y to both sides, y+x=3.
Subtract x from both sides, y=-x+3.
