电子课本网 第109页

第109页

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$解:​ab=(3+2\sqrt{2})(3-2\sqrt{2})=9-8=1​$
$​a+b=3+2\sqrt{2}+3-2\sqrt{2}=6​$
$​a^2b+ab^2=ab(a+b)=6​$
D
$解:原式​=[(2+\sqrt{5})(2-\sqrt{5})]^{2022}(2-\sqrt{5})​$
$​=2-\sqrt{5}$
$解:原式​=[(\sqrt{3}-\sqrt{6})+\sqrt{5}][(\sqrt{3}-\sqrt{6})-\sqrt{5}]​$
$​=(\sqrt{3}-\sqrt{6})²-(\sqrt{5})²​$
$​=3-6\sqrt{2}+6-5​$
$​=4-6\sqrt{2}​$
$解​:x-y=(2+\sqrt{3})²-(2-\sqrt{3})²=8\sqrt{3}​$
$原式​=(x-y)²=(8\sqrt{3})²=192​$
$解:原式​=\sqrt{3+2\sqrt{3}+1}​$
$​=\sqrt{(\sqrt{3}+1)²}​$
$​=\sqrt{3}+1​$
$解:原式​=\sqrt{5-2\sqrt{15}+3}​$
$​=\sqrt{(\sqrt{5}-\sqrt{3})²}​$
$​=\sqrt{5}-\sqrt{3}$