more solutions

math-replay/algebra/solving-for-a-variable.haml

@@ -147,3 +147,31 @@
         m & = & n - 7p - 11 \over 8 \\
         \end{eqnarray}
         $$
+
+    %h2 Solve for $x$ (again):
+    #solve-for-x2-01.solution
+      :escaped
+        $$
+        \begin{eqnarray}
+        7xy + 4xz + x + 1 & = & y + 6 \\
+        7xy + 4xz + x + 1 - 1 & = & y + 6 - 1 \\
+        7xy + 4xz + x & = & y + 5 \\
+        x \cdot (7y + 4z + 1) & = & y + 5 \\
+        x \cdot (7y + 4z + 1) \over 7y + 4z + 1 & = & y + 5 \over 7y + 4z + 1 \\
+        x & = & y + 5 \over 7y + 4z + 1 \\
+        \end{eqnarray}
+        $$
+
+    %h2 Solve for $v$:
+    #solve-for-v-01.solution
+      :escaped
+        $$
+        \begin{eqnarray}
+        3vw - 2vx + 10v + 1 & = & w + 4 \\
+        3vw - 2vx + 10v + 1 - 1 & = & w + 4 - 1 \\
+        3vw - 2vx + 10v & = & w + 3 \\
+        v \cdot (3w - 2x + 10) & = & w + 3 \\
+        v \cdot (3w - 2x + 10) \over 3w - 2x + 10 & = & w + 3 \over 3w - 2x + 10 \\
+        v & = & w + 3 \over 3w - 2x + 10 \\
+        \end{eqnarray}
+        $$