diff --git a/一些有趣的线代题目.md b/一些有趣的线代题目.md
index fb98978..2f2b23c 100644
--- a/一些有趣的线代题目.md
+++ b/一些有趣的线代题目.md
@@ -62,11 +62,11 @@ $$\text{rank}(A - E) =  k$$
 (1) ∵ $AB = 2A - B$
 
 $$
-\therefore (A - 2E)(B + E) = -2E
+\therefore (A + E)(B - 2E) = -2E
 $$
 
 $$
-\therefore (A - 2E)(B + E) = (B + E)(A - 2E)
+\therefore ( B - 2E)(A + E) = (A + E)(B - 2E)
 $$
 
 $$