x十6×二0、4

x十6×二0.4
7x=0.4
x=0.4/7
x=2/35

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x十6×=0.4
解：(1+6)x=0.4
7x=0.4
x=0.4÷7
x=2/35

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x+6x=0.4
7x=0.4
x=0.4/7
x=35/2

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