Evaluate
\frac{-9\sqrt{6}-21}{5}\approx -8.609081537
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\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{\left(7\sqrt{2}-6\sqrt{3}\right)\left(7\sqrt{2}+6\sqrt{3}\right)}
Rationalize the denominator of \frac{3\sqrt{2}}{7\sqrt{2}-6\sqrt{3}} by multiplying numerator and denominator by 7\sqrt{2}+6\sqrt{3}.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{\left(7\sqrt{2}\right)^{2}-\left(-6\sqrt{3}\right)^{2}}
Consider \left(7\sqrt{2}-6\sqrt{3}\right)\left(7\sqrt{2}+6\sqrt{3}\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{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{7^{2}\left(\sqrt{2}\right)^{2}-\left(-6\sqrt{3}\right)^{2}}
Expand \left(7\sqrt{2}\right)^{2}.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{49\left(\sqrt{2}\right)^{2}-\left(-6\sqrt{3}\right)^{2}}
Calculate 7 to the power of 2 and get 49.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{49\times 2-\left(-6\sqrt{3}\right)^{2}}
The square of \sqrt{2} is 2.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{98-\left(-6\sqrt{3}\right)^{2}}
Multiply 49 and 2 to get 98.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{98-\left(-6\right)^{2}\left(\sqrt{3}\right)^{2}}
Expand \left(-6\sqrt{3}\right)^{2}.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{98-36\left(\sqrt{3}\right)^{2}}
Calculate -6 to the power of 2 and get 36.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{98-36\times 3}
The square of \sqrt{3} is 3.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{98-108}
Multiply 36 and 3 to get 108.
\frac{3\sqrt{2}\left(7\sqrt{2}+6\sqrt{3}\right)}{-10}
Subtract 108 from 98 to get -10.
\frac{21\left(\sqrt{2}\right)^{2}+18\sqrt{3}\sqrt{2}}{-10}
Use the distributive property to multiply 3\sqrt{2} by 7\sqrt{2}+6\sqrt{3}.
\frac{21\times 2+18\sqrt{3}\sqrt{2}}{-10}
The square of \sqrt{2} is 2.
\frac{42+18\sqrt{3}\sqrt{2}}{-10}
Multiply 21 and 2 to get 42.
\frac{42+18\sqrt{6}}{-10}
To multiply \sqrt{3} and \sqrt{2}, multiply the numbers under the square root.
Examples
Quadratic equation
{ 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}