165% of what? If you mean 165% of 1, that's 1.65, which is 1 and 13/20
I would say that the last one would be the most accurate.
Add the 6x to both sides. Then divide both sides by 2 to get y by itself.
y <= 6x + 42
Note: if it were a -2y, you’d have to flip the inequality sign when dividing by that negative 2.
:)