Evaluate
-\frac{24\sqrt{5}}{5}-10\approx -20.733126292
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\frac{-2-4\sqrt{5}}{3-\sqrt{5}-\sqrt{5}+2}
Subtract 3 from 1 to get -2.
\frac{-2-4\sqrt{5}}{3-2\sqrt{5}+2}
Combine -\sqrt{5} and -\sqrt{5} to get -2\sqrt{5}.
\frac{-2-4\sqrt{5}}{5-2\sqrt{5}}
Add 3 and 2 to get 5.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{\left(5-2\sqrt{5}\right)\left(5+2\sqrt{5}\right)}
Rationalize the denominator of \frac{-2-4\sqrt{5}}{5-2\sqrt{5}} by multiplying numerator and denominator by 5+2\sqrt{5}.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{5^{2}-\left(-2\sqrt{5}\right)^{2}}
Consider \left(5-2\sqrt{5}\right)\left(5+2\sqrt{5}\right). Multiplication can be transformed into difference of squares using the rule: \left(a-b\right)\left(a+b\right)=a^{2}-b^{2}.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{25-\left(-2\sqrt{5}\right)^{2}}
Calculate 5 to the power of 2 and get 25.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{25-\left(-2\right)^{2}\left(\sqrt{5}\right)^{2}}
Expand \left(-2\sqrt{5}\right)^{2}.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{25-4\left(\sqrt{5}\right)^{2}}
Calculate -2 to the power of 2 and get 4.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{25-4\times 5}
The square of \sqrt{5} is 5.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{25-20}
Multiply 4 and 5 to get 20.
\frac{\left(-2-4\sqrt{5}\right)\left(5+2\sqrt{5}\right)}{5}
Subtract 20 from 25 to get 5.
\frac{-10-4\sqrt{5}-20\sqrt{5}-8\left(\sqrt{5}\right)^{2}}{5}
Apply the distributive property by multiplying each term of -2-4\sqrt{5} by each term of 5+2\sqrt{5}.
\frac{-10-24\sqrt{5}-8\left(\sqrt{5}\right)^{2}}{5}
Combine -4\sqrt{5} and -20\sqrt{5} to get -24\sqrt{5}.
\frac{-10-24\sqrt{5}-8\times 5}{5}
The square of \sqrt{5} is 5.
\frac{-10-24\sqrt{5}-40}{5}
Multiply -8 and 5 to get -40.
\frac{-50-24\sqrt{5}}{5}
Subtract 40 from -10 to get -50.
Examples
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{ x } ^ { 2 } - 4 x - 5 = 0
Trigonometry
4 \sin \theta \cos \theta = 2 \sin \theta
Linear equation
y = 3x + 4
Arithmetic
699 * 533
Matrix
\left[ \begin{array} { l l } { 2 } & { 3 } \\ { 5 } & { 4 } \end{array} \right] \left[ \begin{array} { l l l } { 2 } & { 0 } & { 3 } \\ { -1 } & { 1 } & { 5 } \end{array} \right]
Simultaneous equation
\left. \begin{cases} { 8x+2y = 46 } \\ { 7x+3y = 47 } \end{cases} \right.
Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
\int _ { 0 } ^ { 1 } x e ^ { - x ^ { 2 } } d x
Limits
\lim _{x \rightarrow-3} \frac{x^{2}-9}{x^{2}+2 x-3}