Reach for the Summit - M-S1-A1

Algebra Level 2

Let set $A=\{x|x=a^2+b^2, a,b \in \mathbb Z\}$.

If $x_1,x_2 \in A$, is it always true that $x_1 \cdot x_2 \in A$?

Reach for the Summit problem set - Mathematics

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