Question 29452
You have it correctly worked out.

Solve for y:
{{{Ax+By+C = 0}}}  Subtract Ax from both sides.
{{{By+C = -Ax}}}  Subtract C from both sides.
{{{By = -Ax-C}}} Finally, divide both sides by B
{{{y = (-Ax-C)/B}}} which is what you have.