Typo (userguide).
diff --git a/src/site/xdoc/userguide/linear.xml b/src/site/xdoc/userguide/linear.xml
index 3a061e3..6cad531 100644
--- a/src/site/xdoc/userguide/linear.xml
+++ b/src/site/xdoc/userguide/linear.xml
@@ -118,7 +118,7 @@
           For example, to solve the linear system
           <pre>
            2x + 3y - 2z = 1
-           -x + 7y + 6x = -2
+           -x + 7y + 6z = -2
            4x - 3y - 5z = 1
           </pre>
           Start by decomposing the coefficient matrix A (in this case using LU decomposition)