Datrys {r}{2sqrt{20}-sqrt{5}}{+3sqrt{1/5}}

$$\left. \begin{array} { r } { 2 \sqrt { 20 } - \sqrt { 5 } } \\ { + 3 \sqrt { \frac { 1 } { 5 } } } \end{array} \right.$$

Enrhifo

$$\frac{18\sqrt{5}}{5}\approx 8.049844719$$

Camau Ateb

Ffactora 20=2^{2}\times 5. Ailysgrifennu ail isradd y lluoswm \sqrt{2^{2}\times 5} fel lluoswm ail israddau \sqrt{2^{2}}\sqrt{5}. Cymryd isradd 2^{2}.

$$2\times 2\sqrt{5}-\sqrt{5}+3\sqrt{\frac{1}{5}}$$

Lluosi 2 a 2 i gael 4.

$$4\sqrt{5}-\sqrt{5}+3\sqrt{\frac{1}{5}}$$

Cyfuno 4\sqrt{5} a -\sqrt{5} i gael 3\sqrt{5}.

$$3\sqrt{5}+3\sqrt{\frac{1}{5}}$$

Ailysgrifennu ail isradd y rhaniad \sqrt{\frac{1}{5}} fel rhaniad ail israddau \frac{\sqrt{1}}{\sqrt{5}}.

$$3\sqrt{5}+3\times \frac{\sqrt{1}}{\sqrt{5}}$$

Cyfrifo ail isradd 1 a chael 1.

$$3\sqrt{5}+3\times \frac{1}{\sqrt{5}}$$

Mae'n rhesymoli enwadur \frac{1}{\sqrt{5}} drwy luosi'r rhifiadur a'r enwadur â \sqrt{5}.

$$3\sqrt{5}+3\times \frac{\sqrt{5}}{\left(\sqrt{5}\right)^{2}}$$

Sgwâr \sqrt{5} yw 5.

$$3\sqrt{5}+3\times \frac{\sqrt{5}}{5}$$

Mynegwch 3\times \frac{\sqrt{5}}{5} fel ffracsiwn unigol.

$$3\sqrt{5}+\frac{3\sqrt{5}}{5}$$

Cyfuno 3\sqrt{5} a \frac{3\sqrt{5}}{5} i gael \frac{18}{5}\sqrt{5}.

$$\frac{18}{5}\sqrt{5}$$