From f99ae1651ae56c80a3be353868d4be0bbe80321f Mon Sep 17 00:00:00 2001
From: Petr Skoda <commits@skodak.org>
Date: Sun, 5 Mar 2023 12:20:25 +0100
Subject: [PATCH] MDL-77524 filter_algebra: fix error message

---
 filter/algebra/filter.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/filter/algebra/filter.php b/filter/algebra/filter.php
index 61fe8e7017b..53e22a1ec1f 100644
--- a/filter/algebra/filter.php
+++ b/filter/algebra/filter.php
@@ -237,7 +237,7 @@ class filter_algebra extends moodle_text_filter {
                   $DB->insert_record("cache_filters", $texcache, false);
                   $text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texexp, '', '', $align), $text);
                } else {
-                  $text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> ",$text);
+                  $text = str_replace( $matches[0][$i],"<b>Undetermined error:</b> " . $matches[0][$i], $text);
                }
             } else {
                $text = str_replace( $matches[0][$i], filter_algebra_image($filename, $texcache->rawtext), $text);