the rest of the video

math-replay/algebra/order-of-operations.tex

@@ -57,6 +57,37 @@ ans & = & \frac{-47}{3}
 
 3d.
 \begin{eqnarray*}
+ans & = & \frac{x^2 - z^2}{xz - 2x(z - x)} \mbox{ when } x = -1 \mbox{ and } z = 3 \\
+ans & = & \frac{-1^2 - 3^2}{-1 \times 3 - 2 \times -1 \times (3 - -1)} \\
+ans & = & \frac{1 - 9}{-3 - 2(-1) \times 4} \\
+ans & = & \frac{-8}{-3 - -2 \times 4} \\
+ans & = & \frac{-8}{-3 - -8} \\
+ans & = & \frac{-8}{5}
+\end{eqnarray*}
+
+4b.
+\begin{eqnarray*}
+12 \div 4 + 10 - 3 \times 3 + 7 & = & 11 \\
+3 + 10 - 9 + 7 & = & 11 \\
+13 - 9 + 7 & = & 11 \\
+4 + 7 & = & 11 \\
+11 & = & 11
+\end{eqnarray*}
+
+4d.
+\begin{eqnarray*}
+12 - 8 - 4 \times 5 & = & -8 \\
+12 - 8 - 20 & = & -8 \\
+4 - 20 & = & -8 \\
+-16 & = & -8
+\end{eqnarray*}
+
+\begin{eqnarray*}
+12 - 8 - 4 \times 5 & = & -8 \\
+12 - (8 - 4) \times 5 & = & -8 \\
+12 - 4 \times 5 & = & -8 \\
+12 - 20 & = & -8 \\
+-8 & = & -8
 \end{eqnarray*}
 
 \end{document}