Question

Expliciteaza modulul:a) |√5-√7|
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Answer 1

$|a|=\left \{ {{a,a>0} \atop {-a,a<0}} \right. \\\sqrt{5} < \sqrt{7} \Rightarrow \sqrt{5} -\sqrt{7} <0\\\Rightarrow |\sqrt{5} -\sqrt{7} |=-(\sqrt{5} -\sqrt{7})=-\sqrt{5} +\sqrt{7}$