展开 ((-x+11)(x-10))/2

解答

展开

\frac{( - x + 11 ) ( x - 10 )}{2}

- \frac{x ^{2}}{2} + \frac{21 x}{2} - 55

求解步骤

\frac{( - x + 11 ) ( x - 10 )}{2}

乘开

(- x + 11) (x - 10) : - x^{2} + 21 x - 110

= \frac{- x ^{2} + 21 x - 110}{2}

使用分式法则:

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

\frac{- x ^{2} + 21 x - 110}{2} = - \frac{x ^{2}}{2} + \frac{21 x}{2} - \frac{110}{2}

= - \frac{x ^{2}}{2} + \frac{21 x}{2} - \frac{110}{2}

数字相除:

\frac{110}{2} = 55

= - \frac{x ^{2}}{2} + \frac{21 x}{2} - 55

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