Evaluate
-7\sqrt{5}\approx -15.652475842
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\sqrt{5}-4\times 2\sqrt{5}
Factor 20=2^{2}\times 5. Rewrite the square root of the product \sqrt{2^{2}\times 5} as the product of square roots \sqrt{2^{2}}\sqrt{5}. Take the square root of 2^{2}.
\sqrt{5}-8\sqrt{5}
Multiply -4 and 2 to get -8.
-7\sqrt{5}
Combine \sqrt{5} and -8\sqrt{5} to get -7\sqrt{5}.
Examples
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y = 3x + 4
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\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]
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\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
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Limits
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