Solve for x
x=8
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84=\frac{21}{2}x
Multiply \frac{1}{2} and 21 to get \frac{21}{2}.
\frac{21}{2}x=84
Swap sides so that all variable terms are on the left hand side.
x=84\times \frac{2}{21}
Multiply both sides by \frac{2}{21}, the reciprocal of \frac{21}{2}.
x=\frac{84\times 2}{21}
Express 84\times \frac{2}{21} as a single fraction.
x=\frac{168}{21}
Multiply 84 and 2 to get 168.
x=8
Divide 168 by 21 to get 8.
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