NPC Code:
3y + 7x < 18 // start with this
3y < 18 - 7x // move x to other side by minusing
// 7x from each side
y < (18 - 7x)/3 // divide both sides by 3
y < -(7/3)x + 6 // simplify (I think you can do distributing,
// been a while since Algebra though
I assume you're solving for y
notice that it's very much like trying to get to
y = mx + b. Just remember if you divide by a negative you need to flip the inequality (> or <) sign.
61900933 if you need more help