$a = $_POST['a'];
$b = $_POST['b'];
$c = $_POST['c'];
echo "Zmienna a = ".$a.'
'."Zmienna b = ".$b.'
'."Zmienna c = ".$c."
";
echo "Wzór:"."
"."(x = a^2 + √b - c)/(2a) - (a - √a)/(b)"."
";
$x = ((($a * $a) + sqrt($b) - $c) / (2 * $a)) - (($a - sqrt($a)) / $b);
echo "
x = " . $x;