Linear Algebra/Notation

Lower case Greek alphabet
$ \begin{array}{ll

About the Cover. This is Cramer's Rule for the system $$x_1+2x_2=6$$, $$3x_1+x_2=8$$. The size of the first box is the determinant shown (the absolute value of the size is the area). The size of the second box is $$x_1$$ times that, and equals the size of the final box. Hence, $$x_1$$ is the final determinant divided by the first determinant.