Respuesta :
First, let's clear z from equation 1:
[tex]\begin{gathered} x+3y-2z=6\rightarrow x+3y-6=2z \\ \rightarrow z=\frac{1}{2}x+\frac{3}{2}y-3 \end{gathered}[/tex]Now, let's plug it in equations 2 and 3, respectively:
[tex]\begin{gathered} -4x-7y+3z=3 \\ \rightarrow-4x-7y+3(\frac{1}{2}x+\frac{3}{2}y-3)=3 \\ \\ \rightarrow-4x-7y+\frac{3}{2}x+\frac{9}{2}y-9=3 \\ \\ \rightarrow-\frac{5}{2}x-\frac{5}{2}y=12_{} \\ \end{gathered}[/tex][tex]\begin{gathered} -7x-4y-3z=-5 \\ \rightarrow-7x-4y-3(\frac{1}{2}x+\frac{3}{2}y-3)=-5 \\ \\ \rightarrow-7x-4y-\frac{3}{2}x-\frac{9}{2}y+3=-5 \\ \\ \rightarrow-\frac{17}{2}x-\frac{17}{2}y=-8 \end{gathered}[/tex]We'll have a new system of equations:
[tex]\begin{gathered} -\frac{5}{2}x-\frac{5}{2}y=12_{} \\ \\ -\frac{17}{2}x-\frac{17}{2}y=-8 \end{gathered}[/tex]Now, let's simplify each equation. To do so, we'll multiply the first one by -2/5 and the second one by -2/17. We'll get:
[tex]\begin{gathered} x+y=-\frac{24}{5} \\ \\ x+y=\frac{16}{17} \end{gathered}[/tex]Now, let's solve each equation for y to see them as a pair of line equations:
[tex]\begin{gathered} y=-x-\frac{24}{5}_{} \\ \\ y=-x+\frac{16}{17} \end{gathered}[/tex]Notice that this lines have the same slope. Therefore, they're parallel and do not intercept.
This way, we can conlcude that the original system has no solution.
