ZA-SAMO 2002 Problem 6

Find all rational numbers $a$ , $b$ , $c$ and $d$ such that $$8a^2 - 3b^2 + 5c^2 + 16d^2 - 10ab + 42cd + 18a + 22b - 2c - 54d = 42,$$ $$15a^2 - 3b^2 + 21c^2 - 5d^2 + 4ab +32cd - 28a + 14b - 54c - 52d = -22.$$