Datrys -frac{sqrt{(20^2)+2(981)(40)-2(981)(0)+20}}{981}

$$- \frac{ \sqrt{ ( { 20 }^{ 2 } )+2(981)(40)-2(981)(0)+20 } }{ 981 }$$

Enrhifo

$$-\frac{10\sqrt{789}}{981}\approx -0.286331741$$

Camau Ateb

Cyfrifo 20 i bŵer 2 a chael 400.

$$-\frac{\sqrt{400+2\times 981\times 40-2\times 981\times 0+20}}{981}$$

Lluosi 2 a 981 i gael 1962.

$$-\frac{\sqrt{400+1962\times 40-2\times 981\times 0+20}}{981}$$

Lluosi 1962 a 40 i gael 78480.

$$-\frac{\sqrt{400+78480-2\times 981\times 0+20}}{981}$$

Adio 400 a 78480 i gael 78880.

$$-\frac{\sqrt{78880-2\times 981\times 0+20}}{981}$$

Lluosi 2 a 981 i gael 1962.

$$-\frac{\sqrt{78880-1962\times 0+20}}{981}$$

Lluosi 1962 a 0 i gael 0.

$$-\frac{\sqrt{78880-0+20}}{981}$$

Tynnu 0 o 78880 i gael 78880.

$$-\frac{\sqrt{78880+20}}{981}$$

Adio 78880 a 20 i gael 78900.

$$-\frac{\sqrt{78900}}{981}$$

Ffactora 78900=10^{2}\times 789. Ailysgrifennu ail isradd y lluoswm \sqrt{10^{2}\times 789} fel lluoswm ail israddau \sqrt{10^{2}}\sqrt{789}. Cymryd isradd 10^{2}.

$$-\frac{10\sqrt{789}}{981}$$