Evaluate
\frac{8\sqrt{21}}{7}-\frac{1}{4}\approx 4.987229366
Factor
\frac{32 \sqrt{21} - 7}{28} = 4.987229365663817
Share
Copied to clipboard
\frac{3\sqrt{\frac{6+2}{3}}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Multiply 2 and 3 to get 6.
\frac{3\sqrt{\frac{8}{3}}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Add 6 and 2 to get 8.
\frac{3\times \frac{\sqrt{8}}{\sqrt{3}}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Rewrite the square root of the division \sqrt{\frac{8}{3}} as the division of square roots \frac{\sqrt{8}}{\sqrt{3}}.
\frac{3\times \frac{2\sqrt{2}}{\sqrt{3}}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Factor 8=2^{2}\times 2. Rewrite the square root of the product \sqrt{2^{2}\times 2} as the product of square roots \sqrt{2^{2}}\sqrt{2}. Take the square root of 2^{2}.
\frac{3\times \frac{2\sqrt{2}\sqrt{3}}{\left(\sqrt{3}\right)^{2}}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Rationalize the denominator of \frac{2\sqrt{2}}{\sqrt{3}} by multiplying numerator and denominator by \sqrt{3}.
\frac{3\times \frac{2\sqrt{2}\sqrt{3}}{3}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
The square of \sqrt{3} is 3.
\frac{3\times \frac{2\sqrt{6}}{3}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
To multiply \sqrt{2} and \sqrt{3}, multiply the numbers under the square root.
\frac{2\sqrt{6}}{\frac{1}{2}}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Cancel out 3 and 3.
2\sqrt{6}\times 2\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Divide 2\sqrt{6} by \frac{1}{2} by multiplying 2\sqrt{6} by the reciprocal of \frac{1}{2}.
4\sqrt{6}\sqrt{\frac{2}{7}}-\frac{1}{8}\sqrt{4}
Multiply 2 and 2 to get 4.
4\sqrt{6}\times \frac{\sqrt{2}}{\sqrt{7}}-\frac{1}{8}\sqrt{4}
Rewrite the square root of the division \sqrt{\frac{2}{7}} as the division of square roots \frac{\sqrt{2}}{\sqrt{7}}.
4\sqrt{6}\times \frac{\sqrt{2}\sqrt{7}}{\left(\sqrt{7}\right)^{2}}-\frac{1}{8}\sqrt{4}
Rationalize the denominator of \frac{\sqrt{2}}{\sqrt{7}} by multiplying numerator and denominator by \sqrt{7}.
4\sqrt{6}\times \frac{\sqrt{2}\sqrt{7}}{7}-\frac{1}{8}\sqrt{4}
The square of \sqrt{7} is 7.
4\sqrt{6}\times \frac{\sqrt{14}}{7}-\frac{1}{8}\sqrt{4}
To multiply \sqrt{2} and \sqrt{7}, multiply the numbers under the square root.
\frac{4\sqrt{14}}{7}\sqrt{6}-\frac{1}{8}\sqrt{4}
Express 4\times \frac{\sqrt{14}}{7} as a single fraction.
\frac{4\sqrt{14}}{7}\sqrt{6}-\frac{1}{8}\times 2
Calculate the square root of 4 and get 2.
\frac{4\sqrt{14}}{7}\sqrt{6}+\frac{-2}{8}
Express -\frac{1}{8}\times 2 as a single fraction.
\frac{4\sqrt{14}}{7}\sqrt{6}-\frac{1}{4}
Reduce the fraction \frac{-2}{8} to lowest terms by extracting and canceling out 2.
\frac{4\sqrt{14}\sqrt{6}}{7}-\frac{1}{4}
Express \frac{4\sqrt{14}}{7}\sqrt{6} as a single fraction.
\frac{4\times 4\sqrt{14}\sqrt{6}}{28}-\frac{7}{28}
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of 7 and 4 is 28. Multiply \frac{4\sqrt{14}\sqrt{6}}{7} times \frac{4}{4}. Multiply \frac{1}{4} times \frac{7}{7}.
\frac{4\times 4\sqrt{14}\sqrt{6}-7}{28}
Since \frac{4\times 4\sqrt{14}\sqrt{6}}{28} and \frac{7}{28} have the same denominator, subtract them by subtracting their numerators.
\frac{32\sqrt{21}-7}{28}
Do the multiplications in 4\times 4\sqrt{14}\sqrt{6}-7.
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}