where
- $x$-intercepts at $x=b,c,d,e$
+
+## Literal equations
+
+Equations with multiple pronumerals. Solutions are expressed in terms of pronumerals (parameters))
+
+## Simultaneous equations (linear)
+
+- **Unique solution** - lines intersect at point
+- **Infinitely many solutions** - lines are equal
+- **No solution** - lines are parallel
+
+Solving in matrix form - use inverse $A^{-1}= {1 \over {ad-bc}}\begin{bmatrix}d & -b \\ -c & a\end{bmatrix}$. $A^{-1}$ exists for infinite solutions or no solutions ($ad-bc=0$), does not exist for unique solutions ($ad-bc \ne 0$).
+Or use Matrix -> `det` on CAS.
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