Error when using multiple else/if and elseif statements?

I am currently writing a script and cant figure out why there is a conflict? How can i fix this?

if($a == X)
{
	if(X !== $b){
	echo $a_1+$b_1+$b_2;
	}else{
	echo $a_1+$b_1+$c_1;
	}
}
elseif($a_2 == /)
{
echo $a_1+$a_2+$b_1;
}
else
{
echo $a_1+$a_2;
}
echo '</td><td>'. $b. ' | ' ;
if($b == X)
{
echo ' ';
}
else
{
echo $b_2;
}

PHP:

 

Edit: I think I gave bad info...let me think about that some more...can you post the error?

 

Thanks, I am not getting any specific error in any error log, it simply says there is an error on line 9, 13 and 24. So on elseif, else, and echo $b_2 it says there is some kind of error

 

What is this line checking?

elseif($a_2 == /)

If you're trying to compare a string you'll need quotes: "/"

 

Thanks, that solved the problem. Didnt even consider that the / was an issue

 

/ is an operator so without quotes it would obviously give an error.

echo a; // Outputs a + notice level error
echo /; // Gives error
echo 'a'; // No error
echo '/'; // No error

Code (markup):