An informal introduction to the [[Jacobi Method]]. For a [[System of Linear Equations]], the $n$-th equation is used to find $x_n$ by using all of the other values of $x$. $\huge \begin{align} \begin{cases} 3x_{1}-x_{2}-x_{3}&=7 \\ 2x_{1}+4x_{2}-x_{3} & =-1 \\ -x_{1}+x_{2}-4x_{3} & =-4 \end{cases} \end{align} $