解:(1)5x-2.3=3.7,
5x-2.3+2.3=3.7+2.3,
5x=6,
5x÷5=6÷5,
x=1.2;
(2)
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x+
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x=
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,
(
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+
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)x=
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,
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x=
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,
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x×
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=
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×
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,
x=
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;
(3)x:1.25=1.6:0.25,
0.25x=1.25×1.6,
0.25x÷0.25=1.25×1.6÷0.25,
x=8.
分析:(1)根據(jù)等式的性質(zhì),兩邊同加上2.3,再同除以5即可;
(2)原式變?yōu)椋?img class='latex' src='http://thumb.zyjl.cn/pic5/latex/602.png' />+
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)x=
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,即
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x=
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,根據(jù)等式的性質(zhì),兩邊同乘
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即可;
(3)先根據(jù)比例的性質(zhì)改寫成0.25x=1.25×1.6,再根據(jù)等式的性質(zhì),兩邊同除以0.25即可.
點評:此題考查了運用等式的性質(zhì)解方程,即等式兩邊同加上或同減去、同乘上或同除以一個數(shù)(0除外),兩邊仍相等,同時注意“=”上下要對齊.