第26页

信息发布者：
B
C
B
D
$\frac{15}{2}$
$\frac{11}{28}$
$\frac{5}{16}$
1.99
12
$\frac{1}{4}$
$\frac{3}{4}$
4
​$ \begin {aligned}&=7.5+2.5×0.4×13 \\&=7.5+1×13 \\&=7.5+13 \\&=20.5 \end {aligned} $​
​$ \begin {aligned} &=\frac {6}{7}×\frac {11}{12}×\frac {14}{9}\\&=\frac {11}{14}×\frac {14}{9}\\&=\frac {11}{9} \end {aligned} $​
​$ \begin {aligned} &=\frac {3}{4}÷(\frac {21}{20}×\frac {3}{7})\\&=\frac {3}{4}÷\frac {9}{20} \\&=\frac {3}{4}×\frac {20}{9} \\&=\frac {5}{3} \end {aligned} $​
解：
$ \begin{aligned} \frac{2}{5}x&=2.4×5\\ \frac{2}{5}x&=12\\ x&=12÷\frac{2}{5}\\ x&=30 \end{aligned} $
解：
$ \begin{aligned} 5x&=9×3\\ 5x&=27\\ x&=5.4 \end{aligned} $
解：
$ \begin{aligned} 0.5x&=4×0.8\\ 0.5x&=3.2\\ x&=6.4 \end{aligned} $
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