Answer
Yes, the ordered pair is a solution to the system.
Work Step by Step
Plug in the given values to the variables to test if they are a solution to the system.
$(2,-1,3)$
$x+y+z=4$
$2-1+3=4$
$4=4$
$x-2y-z=1$
$2-2(-1)-3=1$
$2+2-3=1$
$1=1$
$2x-y-2z=-1$
$2(2)-(-1)-2(3)=-1$
$4+1-6=-1$
$-1=-1$
yes
