I am studying linear algebra right now and my textbook says something about unknowns in linear systems. The number of linear equations is represented by the variable "m" and the unknowns are represented by the variable "n". I have tried researching what unknowns are in the internet but could not find any answer to my question. As a result, what are unknowns? Are they the coefficient's of each variable in each equation? Thanks
The unknowns are just the variables. E.g. if I have the system $$x+y=1, \quad x-2y=7, \quad 3x+4y=12$$ that's a system of three equations in two unknowns ($x$ and $y$). So in this case $m=3$ and $n=2$.
Note that this terminology makes good sense if we're trying to solve a system of equations: the idea is that each variable represents some value that is fixed, but which we don't know yet - that is, an unknown!