解:(1)x+x=
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,
2x=
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,
x=
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,
x=
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;
(2)x:4=
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:
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,
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x=4×
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,
x=
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4,
x=
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;
(3)3x+1.2=4.5,
3x=4.5-1.2,
3x=3.3,
x=1.1.
分析:(1)x+x=
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,先把未知数合并,然后等式两边分别除以2,计算即可;
(2)x:4=
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:
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,根据两内项之积等于两外项之积转化为方程,然后解答;
(3)3x+1.2=4.5,根据等式的性质,两边先同减去1.2,然后两边再同时除以3即可.
点评:此题重点考查学生解方程的能力,在解方程时,注意等号要对齐.