展开 ((21x-2)^2)/(340)

解答

展开

\frac{( 21 x - 2 ) ^{2}}{340}

\frac{441 x ^{2}}{340} - \frac{21 x}{85} + \frac{1}{85}

求解步骤

\frac{( 21 x - 2 ) ^{2}}{340}

(21 x - 2)^{2} = 441 x^{2} - 84 x + 4

= \frac{441 x ^{2} - 84 x + 4}{340}

使用分式法则:

\frac{a \pm b}{c} = \frac{a}{c} \pm \frac{b}{c}

\frac{441 x ^{2} - 84 x + 4}{340} = \frac{441 x ^{2}}{340} - \frac{84 x}{340} + \frac{4}{340}

= \frac{441 x ^{2}}{340} - \frac{84 x}{340} + \frac{4}{340}

消掉

\frac{84 x}{340} : \frac{21 x}{85}

= \frac{441 x ^{2}}{340} - \frac{21 x}{85} + \frac{4}{340}

消掉

\frac{4}{340} : \frac{1}{85}

= \frac{441 x ^{2}}{340} - \frac{21 x}{85} + \frac{1}{85}

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