diff --git a/notes/.obsidian/plugins/obsidian-activity-history/data.json b/notes/.obsidian/plugins/obsidian-activity-history/data.json
index ffafb25..97084c8 100644
--- a/notes/.obsidian/plugins/obsidian-activity-history/data.json
+++ b/notes/.obsidian/plugins/obsidian-activity-history/data.json
@@ -12,8 +12,8 @@
   "checkpointList": [
     {
       "path": "/",
-      "date": "2022-04-20",
-      "size": 825890
+      "date": "2022-04-21",
+      "size": 826495
     }
   ],
   "activityHistory": [
@@ -587,6 +587,10 @@
         {
           "date": "2022-04-20",
           "value": 1592
+        },
+        {
+          "date": "2022-04-21",
+          "value": 605
         }
       ]
     }
diff --git a/notes/mat/Rovnice/Soustavy rovnic.md b/notes/mat/Rovnice/Soustavy rovnic.md
index 24f768b..8a61439 100644
--- a/notes/mat/Rovnice/Soustavy rovnic.md	
+++ b/notes/mat/Rovnice/Soustavy rovnic.md	
@@ -285,3 +285,93 @@ $4x-2x=28$
 $2x=28$
 $x=14$ - králíčci
 $(30-x)=16$ - kuřátka
+
+---
+
+$x+y=12$
+$x+z=19$
+$y+z=17$
+
+$x+y=12$
+$x+z=19$
+$y-z=-7$
+
+$y+z=17$
+$-y+z=7$
+
+$2z=24$
+$z=12$
+
+$y+z=17$
+$y+12=17$
+$y=5$
+
+$x+y=12$
+$x+5=12$
+$x=7$
+
+---
+
+$2x+3y=29$
+$3x+4z=44$
+$2y+3z=38$
+
+$6x+9y=87$
+$6x+8z=88$
+$9y-8z=-1$
+
+$18y-16z=-2$
+$18y+27z=342$
+ 
+$z=344/43=8$
+
+---
+
+$4x+2y+z=24$
+$y-2x=-6$
+$z+3x=11$
+
+$3y-6x=-18$
+$2z+6x=22$
+
+---
+
+$x+2y-z=6$
+$2x+4y-2z=12$
+$-7x-14y+7z=-42$
+
+$-z=6-2y-x$
+$z=x+2y-6$
+
+
+$K=\{[x;y;z]: [x;y;x+2y-6]\}; x;y\in\mathbb{R}\}$
+
+---
+
+$2x-y+z=3$
+$3x+y-2z=-1$
+$x-3y+4z=7$
+
+$2x-y+z=3$
+$3x+y-2z=-1$
+$5x-z=2$
+
+$6x+2y-4z=-2$
+$x-3y+4z=7$
+$7x-y=5$
+
+$35x-7z=14$
+$35x-5y=25$
+$2y=11$
+$y=10.5$
+
+---
+
+$2x+y-3z=6$
+$x-y+7z=11$
+$8x+y+5z=50$
+
+$2x+y-3z=6$
+$x-y+7z=11$
+$3x+4z=17$
+