All solutions here are SUGGESTED. Mr. Teng will hold no liability for any errors. Comments are entirely personal opinions.

(i)
$x-2z=4$
$2x-2y+z=6$
$5x-4y+3z=-9$
Using GC, $x=-\frac{38}{3}, y=-\frac{119}{6}, z=-\frac{25}{3}$
$\therefore, (-\frac{38}{3}, -\frac{119}{6}, -\frac{25}{3})$

(ii)
$x-2z=4$
$2x-2y+z=6$
$5x-4y=-9$
Using GC, there is no solutions found. Thus, planes p, q, r have no common intersection at all. They form a triangular prism since none of the planes are parallel to each other.