问题
解答题
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答案
(1)3:8=x:2.4,
8x=3×2.4,
8x÷8=7.2÷8,
x=0.9,
(2)x:5=
:0.5,2 5
0.5x=5×
,2 5
0.5x÷0.5=2÷0.5,
x=4,
(3)
:x=6:8,7 8
6x=
×8,7 8
6x÷6=7÷6,
x=
,7 6
(4)12x=300-4x,
12x+4x=300-4x+4x,
16x=300,
16x÷16=300÷16,
x=18.75,
(5)7x+5.3=7.4,
7x+5.3-5.3=7.4-5.3,
7x=2.1,
7x÷7=2.1÷7,
x=0.3,
(6)(200-x)÷5=30,
(200-x)÷5×5=30×5,
200-x=150,
200-x+x-150=150+x-150,
50=x,
x=50.