) 2x_(1)+x_(2)+x_(3)&-2 4x_(1)+3x_(2)+3x_(3)&+x_(4)-3 8x_(1)+7x_(2)+9x_(3)+5x_(4)&=1 6x_(1)+7x_(2)+9

The correct answer is:<br /><br />$\{ \begin{matrix} 2x_{1}+x_{2}+x_{3}&-2\\ 4x_{1}+3x_{2}+3x_{3}&+x_{4}-3\\ 8x_{1}+7x_{2}+9x_{3}+5x_{4}&=1\\ 6x_{1}+7x_{2}+9x_{3}+5x_{4}&=0\end{matrix}$<br /><br />This is a system of linear equations with four variables $x_1$, $x_2$, $x_3$, and $x_4$. The system can be solved using methods such as substitution, elimination, or matrix operations.