Question

Simplify 4\2-root 2 + 5 \root 2-1

Answer 1

Answer:

Step-by-step explanation:

Use FOIL method

$(\sqrt{2} -1)(2-\sqrt{2})= \sqrt{2}*2 -\sqrt{2}*\sqrt{2} -1*2-1*(-\sqrt{2})\\\\\\=2\sqrt{2} - 2 -2 +\sqrt{2}$

Combine like terms

$=2\sqrt{2} +\sqrt{2} - 2 -2\\\\\\=(2+1)\sqrt{2} - 4\\\\\\=3\sqrt{2}-4$

$\frac{4}{2-\sqrt{2}}+\frac{5}{\sqrt{2} -1}=\frac{4*(\sqrt{2} -1)}{(2-\sqrt{2})*(\sqrt{2} -1)}+\frac{5*(2-\sqrt{2})}{(\sqrt{2} -1)(2-\sqrt{2})}\\\\\\=\frac{4\sqrt{2}-4+10-5\sqrt{2}}{(\sqrt{2} -1)(2-\sqrt{2})}$

$=\frac{4\sqrt{2}-5\sqrt{2}-4+10}{3\sqrt{2}-4}\\\\\\=\frac{(4-5)\sqrt{2}+6}{3\sqrt{2}-4}\\\\\\=\frac{-1\sqrt{2}+6}{3\sqrt{2}-4}$