Question

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Answer 1

$1, B = \frac{\sqrt{{(x + 2)}^{2}}}{\sqrt{x} - \frac{2}{\sqrt{x}}}, đ k : x > 0 = \frac{|x + 2|}{\frac{x - 2}{\sqrt{x}}} = \frac{\sqrt{x} . (x + 2)}{x - 2}, d o x > 0 t h ì x + 2 > 0 V ậ y B = \frac{\sqrt{x} . (x + 2)}{x - 2}$

$2, C = \frac{8 \sqrt{41}}{\sqrt{45 + 4 \sqrt{41}}} + \sqrt{45 - 4 \sqrt{41}} = \frac{8 \sqrt{41}}{\sqrt{41 + 2 . \sqrt{41} + 4}} + \sqrt{41 - 2 \sqrt{41} + 4} = \frac{8 \sqrt{41}}{\sqrt{{(\sqrt{41} + 2)}^{2}}} + \sqrt{{(\sqrt{41} - 2)}^{2}} = \frac{8 \sqrt{41}}{|\sqrt{41} + 2|} + |\sqrt{41} - 2| = \frac{8 \sqrt{41}}{\sqrt{41} + 2} + \sqrt{41} - 2, d o \sqrt{41} \pm 2 > 0 = \frac{8 \sqrt{41} . (\sqrt{41} - 2)}{41 - 4} + \sqrt{41} - 2 = \frac{328 - 16 \sqrt{41}}{37} + \sqrt{41} - 2 = \frac{254}{37} + \frac{53}{37} \sqrt{41} V ậ y C = \frac{254}{37} + \frac{53}{37} \sqrt{41}$ .

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Answer 2

$1, B = \frac{\sqrt{{(x + 2)}^{2}}}{\sqrt{x} - \frac{2}{\sqrt{x}}}, đ k : x > 0 = \frac{|x + 2|}{\frac{x - 2}{\sqrt{x}}} = \frac{\sqrt{x} . (x + 2)}{x - 2}, d o x > 0 t h ì x + 2 > 0 V ậ y B = \frac{\sqrt{x} . (x + 2)}{x - 2}$

$2, C = \frac{8 \sqrt{41}}{\sqrt{45 + 4 \sqrt{41}}} + \sqrt{45 - 4 \sqrt{41}} = \frac{8 \sqrt{41}}{\sqrt{41 + 2 . \sqrt{41} + 4}} + \sqrt{41 - 2 \sqrt{41} + 4} = \frac{8 \sqrt{41}}{\sqrt{{(\sqrt{41} + 2)}^{2}}} + \sqrt{{(\sqrt{41} - 2)}^{2}} = \frac{8 \sqrt{41}}{|\sqrt{41} + 2|} + |\sqrt{41} - 2| = \frac{8 \sqrt{41}}{\sqrt{41} + 2} + \sqrt{41} - 2, d o \sqrt{41} \pm 2 > 0 = \frac{8 \sqrt{41} . (\sqrt{41} - 2)}{41 - 4} + \sqrt{41} - 2 = \frac{328 - 16 \sqrt{41}}{37} + \sqrt{41} - 2 = \frac{254}{37} + \frac{53}{37} \sqrt{41} V ậ y C = \frac{254}{37} + \frac{53}{37} \sqrt{41}$ .

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