Hey TropNul I\'m extremely grateful for all your help! You\'re code works well, except you\'re right, theres a bug. But I don\'t think it\'s because of what you said, I spent an hour or so trying to figure out what it was because it was very confusing. I would try to solve sin(x)=90 (which should return $false) and it would always return -2. It would return false under the old parser and even through all the checks to make sure the answer was legit it still always returned -2. It turned out that the parser couldn\'t support negative numbers with the functions, so sin(-2) wouldn\'t work. I\'m not quite sure but all I need to add is a -? somewhere in the regsubex line? I\'ve also given them different names so that shouldn\'t be a problem.

@Korvin, thanks for the feedback :) However it\'s impossible to add another variable such as Y, this is because you can only solve 1 variable per equation. eg if you consider y + x = 1. This has infinite number of solutions. This primarily solves any single equation. To solve simultaneous equations its infinitely more complicated. I have done it in C# but I think it\'s pretty much close to impossible in mIRC.

You could still solve for any variable in y=mx + c. If you know any 3 values and you are left with a fourth variable.