Toán mọi người giúp mik với (5-6√5)/(√5)+(7-√7)/(√7-1)- (√5+√7) 02/08/2021 By Ximena mọi người giúp mik với (5-6√5)/(√5)+(7-√7)/(√7-1)- (√5+√7)
$\begin{array}{l}\dfrac{5 – 6\sqrt5}{\sqrt5} + \dfrac{7 – \sqrt7}{\sqrt7 – 1} – (\sqrt5 + \sqrt7)\\ = \dfrac{\sqrt5(\sqrt5 – 6)}{\sqrt5} + \dfrac{\sqrt7(\sqrt7 – 1)}{\sqrt7 – 1} – (\sqrt5 + \sqrt7)\\ = \sqrt5 – 6 + \sqrt7 – \sqrt5 – \sqrt7 = – 6\end{array}$ Trả lời
$\dfrac{5-6\sqrt[]{5}}{\sqrt[]{5}}+\dfrac{7-\sqrt[]{7}}{\sqrt[]{7}-1}-(\sqrt[]{5}+\sqrt[]{7})$ $=\dfrac{\sqrt[]{5}(\sqrt[]{5}-6)}{\sqrt[]{5}}+\dfrac{\sqrt[]{7}(\sqrt[]{7}-1)}{\sqrt[]{7}-1}-(\sqrt[]{5}+\sqrt[]{7})$ $=\sqrt[]{5}-6+\sqrt[]{7}-\sqrt[]{5}-\sqrt[]{7}$ $=-6$ Trả lời
$\begin{array}{l}\dfrac{5 – 6\sqrt5}{\sqrt5} + \dfrac{7 – \sqrt7}{\sqrt7 – 1} – (\sqrt5 + \sqrt7)\\ = \dfrac{\sqrt5(\sqrt5 – 6)}{\sqrt5} + \dfrac{\sqrt7(\sqrt7 – 1)}{\sqrt7 – 1} – (\sqrt5 + \sqrt7)\\ = \sqrt5 – 6 + \sqrt7 – \sqrt5 – \sqrt7 = – 6\end{array}$
$\dfrac{5-6\sqrt[]{5}}{\sqrt[]{5}}+\dfrac{7-\sqrt[]{7}}{\sqrt[]{7}-1}-(\sqrt[]{5}+\sqrt[]{7})$
$=\dfrac{\sqrt[]{5}(\sqrt[]{5}-6)}{\sqrt[]{5}}+\dfrac{\sqrt[]{7}(\sqrt[]{7}-1)}{\sqrt[]{7}-1}-(\sqrt[]{5}+\sqrt[]{7})$
$=\sqrt[]{5}-6+\sqrt[]{7}-\sqrt[]{5}-\sqrt[]{7}$
$=-6$