This is a very cool way to make wolfram alpha do the math in your code, using php.

<?php
$app_id = "YOUR_APP_ID";

$x1 = 4;
$y1 = 4;
$input1 = "solve($y1%3Da*$x1%2Bb%2Ca)";
$xmlf1 = "http://api.wolframalpha.com/v2/query?appid=$app_id&input=$input1&format=plaintext";
$xml1 = simplexml_load_file("$xmlf1") or die("Error: Cannot create object");
$a = $xml1->pod[1]->subpod->plaintext;

echo $a;
$antal_tegn = strlen($a);
$a = substr($a, 4, $antal_tegn);
//echo $a;

echo "<br>";

$x2 = 8;
$y2 = 8;
$input2 = "solve($y2%3D$a*$x2%2Bb%2Cb)";
$xmlf2 = "http://api.wolframalpha.com/v2/query?appid=$app_id&input=$input2&format=plaintext";
$xml2 = simplexml_load_file("$xmlf2") or die("Error: Cannot create object");
$b = $xml2->pod[1]->subpod->plaintext;

echo $b;
$antal_tegn = strlen($b);
$b = substr($b, 4, $antal_tegn);
//echo $b;
?>