Revert "Update good-practice.md"

This reverts commit f8a29aa.

Author: CarkHT

docs/teacher/guides/good-practice.md

@@ -72,30 +72,32 @@ Live preview instantly renders a student's input. This is very useful for long/c
 
 ## Latex help
 
-1. Use `\begin{array}` to generate a compact table i.e.  
-        
-        \begin{array}{|c|c|}
-        \hline
-        \theta_{2,0} & \theta_{1,L}\\
-        \hline
-        -6700 & 130.5641\\
-        \hline
-        -6600 & 161.6086\\
-        \hline
-        \end{array}
-    ![Image showing a example of a table](images/table.png)
-
+1. Use `\begin{array}` to generate a compact table i.e. 
+  
+  ```
+  \begin{array}{|c|c|}
+  \hline
+  \theta_{2,0} & \theta_{1,L}\\
+  \hline
+  -6700 & 130.5641\\
+  \hline
+  -6600 & 161.6086\\
+  \hline
+  \end{array}
+  ```
+  
+  ![Image showing a example of a table](images/table.png)
+  
 2. Use `\begin{aligned}` to keep your working formatted nicely
+```
+\begin{aligned}
+M_{d e f} &=\dfrac{1}{2}(M+M^T)\\
+& =\dfrac{1}{2} \begin{pmatrix} 4 & 14\\ -6 & -11 \end{pmatrix}+\begin{pmatrix} 4 & -6\\ 14 & -11 \end{pmatrix}\\
+& =\begin{pmatrix} 4 & 4\\ 4 & -11 \end{pmatrix}
+\end{aligned}
+```
 
-        
-        \begin{aligned}
-        M_{d e f} &=\dfrac{1}{2}(M+M^T)\\
-        & =\dfrac{1}{2} \begin{pmatrix} 4 & 14\\ -6 & -11 \end{pmatrix}+\begin{pmatrix} 4 & -6\\ 14 & -11 \end{pmatrix}\\
-        & =\begin{pmatrix} 4 & 4\\ 4 & -11 \end{pmatrix}
-        \end{aligned}
-
-    ![Image showing a example of a algined working](images/aligned.png)
-
+![Image showing a example of a algined working](images/aligned.png)
 
 3. Use `\left` and `\right` for equations with multiple brackets