Question

Va rog ajutați-mă la exercitiul 7d si 8b! Dau toate punctele pe care le am! Va rog urgent

Answer 1

7d)

$\it \left(\dfrac{4}{5\sqrt2}+\dfrac{3}{\sqrt8}\right)-\left(\dfrac{5\sqrt2}{4}+\dfrac{3}{\sqrt2}\right)= \left(\dfrac{^{\sqrt2)}4}{5\sqrt2}+\dfrac{^{\sqrt2)}3}{2\sqrt2}\right)-\left(\dfrac{5\sqrt2}{4}+\dfrac{^{\sqrt2)}3}{\sqrt2}\right)=\\ \\ \\ = \left(\dfrac{4\sqrt2}{5\cdot2}+\dfrac{3\sqrt2}{2 \cdot2 }\right)-\left(\dfrac{5\sqrt2}{4}+\dfrac{3\sqrt2}{2}\right)= \dfrac{^{2)}4\sqrt2}{10}+\dfrac{^{5)}3\sqrt2}{4}-\dfrac{^{5)}5\sqrt2}{4}-\dfrac{^{10)}3\sqrt2}{2}=$

$\it = \dfrac{8\sqrt2+15\sqrt2-25\sqrt2+30\sqrt2}{20}=\dfrac{53\sqrt2-25\sqrt2}{20}=\dfrac{28\sqrt2^{(4}}{20}=\dfrac{7\sqrt2}{5}$