Answer
the point represent be
$(-1,0,0)$
$(0,-1,0)$
$(0,1,0)$
Work Step by Step
$x_{1}=y_{1}=z_{1}=0$ .
Tetragonal unit cell $a = b \ne c$
Now the point $x_{2}=a$
$y_{2}=0b=0$
and $z_{2}=0c=0$
vector length =$\sqrt{x^2+y^2+z^2}=\sqrt{a^2}=a$
Then the point will be
$(-1,0,0)$
$(0,-1,0)$
$(0,1,0)$
