Evaluate
\frac{2y}{3}-\frac{1}{21}
Factor
\frac{14y-1}{21}
Graph
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\frac{7\times 2y}{21}-\frac{1}{21}
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of 3 and 21 is 21. Multiply \frac{2y}{3} times \frac{7}{7}.
\frac{7\times 2y-1}{21}
Since \frac{7\times 2y}{21} and \frac{1}{21} have the same denominator, subtract them by subtracting their numerators.
\frac{14y-1}{21}
Do the multiplications in 7\times 2y-1.
\frac{14y-1}{21}
Factor out \frac{1}{21}.
Examples
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Matrix
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Simultaneous equation
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Differentiation
\frac { d } { d x } \frac { ( 3 x ^ { 2 } - 2 ) } { ( x - 5 ) }
Integration
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Limits
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