A linear equation is one where the unknowns appear multiplied only
by constants. You can use a shorthand notation for a collection of
such equations which saves time: for example, **2x + 3y = 7**
and **-x + 17y = 3** can be written as

The square array of numbers is called the * matrix* of
the equations and the rectangular column containing **x** and **y**
and the object on the right-hand side of the equals sign are called
(column) vectors.

Wed Jan 31 11:33:59 EST 1996