Đáp án+Giải thích các bước giải:

`A = \sqrt{14+6\sqrt{5}}-\sqrt{8-2\sqrt{15}}`

`A = \sqrt{9+6\sqrt{5}+5}-\sqrt{5-2\sqrt{5.3}+3}`

`A = \sqrt{(3+\sqrt{5})^2}-\sqrt{(\sqrt{5}-\sqrt{3})^2}`

`A = | 3 + \sqrt{5} | - | \sqrt{5} - \sqrt{3} |`

`A = 3 + \sqrt{5} - \sqrt{5} + \sqrt{3}`

`A = 3 + \sqrt{3}`

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`A = \sqrt{9+4\sqrt{2}}-\sqrt{9-4\sqrt{2}}`

`A = \sqrt{8+2\sqrt{8}+1}-\sqrt{8-2\sqrt{8}+1}`

`A = \sqrt{(\sqrt{8}+1)^2}-\sqrt{(\sqrt{8}-1)^2}`

`A = |\sqrt{8}+1|-|\sqrt{8}-1|`

`A = \sqrt{8} + 1 - \sqrt{8} + 1`

`A = 2`

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`A = \sqrt{13-4\sqrt{3}}+\sqrt{7-4\sqrt{3}}`

`A = \sqrt{12-2\sqrt{12}+1}+\sqrt{4-4\sqrt{3}+3}`

`A = \sqrt{(\sqrt{12}-1)^2}+\sqrt{(2-\sqrt{3})^2}`

`A = |\sqrt{12}-1| + |2-\sqrt{3}|`

`A = 2\sqrt{3} - 1 + 2-\sqrt{3}`

`A = 1 +\sqrt{3}`