解:(1)50%x-30=52,
0.5x-30=52,
0.5x-30+30=52+30,
0.5x=82
0.5x÷0.5=82÷0.5,
x=164;
(2)16+4x=40,
16+4x-16=40-16,
4x=24,
4x÷4=24÷4,
x=6;
(3)
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x+
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x=112,
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x=112,
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x÷
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=112÷
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,
x=126.
分析:(1)把50%化成0.5,根据等式的性质,方程两边同加30,再同除以0.5即可;(2)根据等式的性质,方程两边先同减16,再同除以4;(3)先将方程左边合并为
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x,再同除以
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即可得解.
点评:在解方程时应根据等式的性质,即等式两边同加上、同减去、同乘上或同除以某一个数(0除外),等式的两边仍相等,同时注意“=”上下要对齐.