lean_workbook_plus_5259

I'm not sure that you are understanding my solution. The trivial inequality states that for any $a \in \mathbb{R}$ , $a^2 \ge 0$ , with equality at $a = 0$ . Using this with $x-2$ and $y+1$ , we obtain the inequalities $(x-2)^2 \ge 0$ and $(y+1)^2\ge 0$ . Therefore

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