[tex] \sqrt{x ^{2} + 4 } - x - 2[/tex]

[tex] \sqrt{ {x}^{2} + 4 } - x - 2 \\ = ( {x}^{2} + {2}^{2} ) {}^{ \frac{1}{2} } - x - 2 \\ = x + 2 - x - 2 \\ = 0 [/tex]
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