Find the ordered triple (p,q,r) that satisfies the following system:
p - 2q = 3
q - 2r = -2 + q
p + r = 9 + p
p + r = 9 + p means r = 9.
From q - 2r = -2 + q, we have r = 1.
These two equations are contradictory. Hence, the system has no solutions.