第94页

信息发布者：
整式进行加和减实质就是在
化简，先去括号再合并化到最
简才算完.
$\boldsymbol{\frac{x - 3}{6} - \frac{x - 1}{10} = \frac{1}{6}(x - 3) - \frac{1}{10}(x - 1)}$
$\boldsymbol{= \frac{1}{6}x - \frac{1}{2} - \frac{1}{10}x + \frac{1}{10}}$
$\boldsymbol{= \left( \frac{1}{6} - \frac{1}{10} \right)x - \frac{1}{2} + \frac{1}{10}}$
$\boldsymbol{= \left( \frac{5 - 3}{30} \right)x - \frac{5 - 1}{10} = \frac{1}{15}x - \frac{2}{5}}$.
有三种.
方法1：剩下纸片的面积为$10 × (x - 2 + 3) - 3 × (10 - 4) = 10(x + 1) - 18 = 10x - 8$.
方法2：剩下纸片的面积为$3 × 4 + 10(x - 2) = 12 + 10x - 20 = 10x - 8$.
方法3：剩下纸片的面积为$4 × (x - 2 + 3) + (10 - 4) × (x - 2) = 4(x + 1) + 6(x - 2) = 4x + 4 + 6x - 12 = 10x - 8$.
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