Answer
$\left\{\begin{array}{rl}
2x-y+4z & =3\\
-4x+\frac{3}{4}y+\frac{1}{3}z & =-1\\
-3x & =0
\end{array}\right.$
Work Step by Step
The product of the two matrices on the LHS is a 3$\times$1 matrix:
$\left[\begin{array}{l}
2x-y+4z\\
-4x+\frac{3}{4}y+\frac{1}{3}z\\
-3x+0+0
\end{array}\right].\qquad $Equating it to $\left[\begin{array}{l}
3\\
-1\\
0
\end{array}\right]$ leads to
the system of equations
$\left\{\begin{array}{ll}
2x-y+4z & =3\\
-4x+\frac{3}{4}y+\frac{1}{3}z & =-1\\
-3x & =0
\end{array}\right.$
