Đáp án:
Giải thích các bước giải:
$\dfrac{4}{5}.x=\dfrac{4}{7}$
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$⇒x=\dfrac{4}{7}:\dfrac{4}{5}$
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$⇒x=\dfrac{5}{7}$
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$ $
$\dfrac{3}{4}.x=\dfrac{1}{2}$
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$⇒x=\dfrac{1}{2}:\dfrac{3}{4}$
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$⇒x=\dfrac{2}{3}$
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$ $
$\dfrac{4}{7}.x=\dfrac{1}{2}$
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$⇒x=\dfrac{1}{2}:\dfrac{4}{7}$
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$⇒x=\dfrac{7}{8}$
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`4/7:(2/5 . 4/7)`
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`=4/7:8/35`
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`=5/2`
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`=6/7+5/7:5-6/9`
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`=6/7+1/7-6/9`
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`=1-6/9`
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`=1/3`
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`\frac{12}{7}.7/4+\frac{35}{11}`
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`=3+\frac{35}{11}`
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`=\frac{99}{33}+\frac{105}{33}`
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`=\frac{204}{33}=\frac{68}{11}`
