解方程: ①X+0.25X=12.5 ②3.2X-38.2=25.8 ③7.2×0.5+3X=4.8
(1)X+0.25X=12.5,
1.25x=12.5,
1.25x÷1.25=12.5÷1.25,
x=10;
(2)3.2X-38.2=25.8,
3.2X-38.2+38.2=25.8+38.2,
3.2x=64,
3.2x÷3.2=64÷3.2,
x=20;
(3)7.2×0.5+3X=4.8,
3.6+3X=4.8,
3.6+3X-3.6=4.8-3.6,
3x=1.2,
3x÷3=1.2÷3,
x=0.4.
1.25x=12.5,
1.25x÷1.25=12.5÷1.25,
x=10;
(2)3.2X-38.2=25.8,
3.2X-38.2+38.2=25.8+38.2,
3.2x=64,
3.2x÷3.2=64÷3.2,
x=20;
(3)7.2×0.5+3X=4.8,
3.6+3X=4.8,
3.6+3X-3.6=4.8-3.6,
3x=1.2,
3x÷3=1.2÷3,
x=0.4.
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第1个回答 2018-10-20
①X+0.25X=12.5
解:(1+0.25)X=12.5
1.25X=1.25
X=1
②3.2X-38.2=25.8
解:3.2X=64
X=20
③7.2×0.5+3X=4.8
解:36+3X=4.8
39X=4.8
X=0.4
解:(1+0.25)X=12.5
1.25X=1.25
X=1
②3.2X-38.2=25.8
解:3.2X=64
X=20
③7.2×0.5+3X=4.8
解:36+3X=4.8
39X=4.8
X=0.4