#### Answer

$$x+2z=-8 \\ 2x-2y+3z=12 \\ 4x+7y+z =3$$

#### Work Step by Step

In order to write a matrix that would solve a linear equation, we would write the coefficients of each variable in their own column. Thus, we reverse the process to find:
$$x+2z=-8 \\ 2x-2y+3z=12 \\ 4x+7y+z =3$$