Solve for x
x = -\frac{37 \sqrt{7}}{21} \approx -4.661561834
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\sqrt{21}\sqrt{3}x+2\left(\sqrt{21}\right)^{2}=5
Use the distributive property to multiply \sqrt{21} by \sqrt{3}x+2\sqrt{21}.
\sqrt{3}\sqrt{7}\sqrt{3}x+2\left(\sqrt{21}\right)^{2}=5
Factor 21=3\times 7. Rewrite the square root of the product \sqrt{3\times 7} as the product of square roots \sqrt{3}\sqrt{7}.
3\sqrt{7}x+2\left(\sqrt{21}\right)^{2}=5
Multiply \sqrt{3} and \sqrt{3} to get 3.
3\sqrt{7}x+2\times 21=5
The square of \sqrt{21} is 21.
3\sqrt{7}x+42=5
Multiply 2 and 21 to get 42.
3\sqrt{7}x=5-42
Subtract 42 from both sides.
3\sqrt{7}x=-37
Subtract 42 from 5 to get -37.
\frac{3\sqrt{7}x}{3\sqrt{7}}=-\frac{37}{3\sqrt{7}}
Divide both sides by 3\sqrt{7}.
x=-\frac{37}{3\sqrt{7}}
Dividing by 3\sqrt{7} undoes the multiplication by 3\sqrt{7}.
x=-\frac{37\sqrt{7}}{21}
Divide -37 by 3\sqrt{7}.
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