How can I solve with this question?

X^2 + Y^2

there are not X and Y .

I really confusion this one.

Does anyone explain this one?

Ifz = a + 19 and w = c + id, the equivalent rules lzllwl = lzwl or Q(z)Q(w) = Q(zw) amount to1 (a2 + 222ch + d2) = x2 + 39 where the set {w} = l:] - This identity allows us to easily see an interesting number theoretical fact: if two natural numbers n a integer squares, then so is their product! 2 Let's illustrate this by noting that if a = 9 and b = 3, then a + b2 = 90, and similarly if c = 5 anc c2 + d2 = 29. So we can write where the set {x, y} = Note: the Maple syntax for the set {1, 2} is {1.2}. 90x29=2610=x2+y2. \