Answer
$a. $
$\left\{\begin{array}{l}
x-2z+2w=5\\
y+3z=-1\\
z-w=0\\
w=-1
\end{array}\right.$
$b.$
$(5,2,-1,-1)$
Work Step by Step
$a. $
$\left\{\begin{array}{l}
x-2z+2w=5\\
y+3z=-1\\
z-w=0\\
w=-1
\end{array}\right.$
$b.$
Back substitute $w=-1 $ into
$z-w=0$
$z-(-1)=0$
$z+1=0$
$z=-1$
Back substitute $z=-1 $ into
$y+3z=-1$
$y+3(-1)=-1$
$y-3=-1$
$y=2$
Back substitute $, z=-1,w=-1 $ into
$x-2(-1)+2(-1)=5$
$x+2-2=5$
$x=5$
Solution: $(5,2,-1,-1)$
