PHP algorithm for solving a simple linear equation.

[ftpkid]

Hello, I'm a beginner and i just wrote an extremely simple program for solving a linear equation. It works, but i was wondering if you guys can take a look. Here it is:

<?php$a = 5;$b = 10;$r = -($b/$a);if($a == 0 && $b == 0) {echo 'There are infinitely many solutions';}elseif($a>0 && $b>0) {echo $r;}elseif($a>0 && $b == 0) {echo 'X is equal to zero';}else {echo 'There are no solutions';}?>

It's really, really basic and some parts aren't really correct(i guess). Please, tell me what you think. It isn't really complete, because the variable "a", might be a negative number. Also the code isn't exactly the most beautiful one... I didn't make an HTML form, so that the user can write the constants, on purpose.

[justsomeguy]

You should check if $a is zero before doing the division.

[Ingolme]

Your code doesn't seem to be accurate for negative values of A and B. It seems you did note that in your post. Is this the equation you're trying to solve? x = -(b/a)

[ftpkid]

Your code doesn't seem to be accurate for negative values of A and B. It seems you did note that in your post. Is this the equation you're trying to solve? x = -(b/a)

Yes, that's it.

[Ingolme]

There's a simpler way to do it: As long as $a is not 0, perform the division. If $a is 0 then check the value of $b. If $b is 0 then there are infinite possile answers, otherwise the answer is infinity.