问题
解答题
解比例和方程.
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答案
(1)75:x=25:15,
25x=75×15,
25x÷25=1125÷25,
x=45;
(2)24%x+8%x=16,
32%x=16,
32%x÷32%=16÷32%,
x=50;
(3)1.8:x=
:3 4
,1 4
x=1.8×3 4
,1 4
x÷3 4
=3 4
÷9 20
,3 4
x=
;3 5
(4)
=0.25 x
,0.5 2
0.5x=0.25×2,
0.5x÷0.5=0.5÷0.5,
x=1.