Question 20
Find the number of ordered triples of positive integers $(a,b,c)$ with $1\le a,b,c\le10$ such that
$$a^2+b^2+c^2+2ab+2a(c-1)+2b(c+1)$$
is a perfect square.
$$a^2+b^2+c^2+2ab+2a(c-1)+2b(c+1)$$
is a perfect square.
SEAMO · SEAMO 2027 - Paper F - SET 10 - Self-study