解:(1)
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x-75%x=1.8,
(1.25-0.75)x=1.8,
0.5x=1.8,
0.5x÷0.5=1.8÷0.5,
x=3.6;
(2)0.8X=
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,
0.8X=0.4,
0.8X÷0.8=0.4÷0.8,
X=0.5.
分析:(1)先根據(jù)乘法分配律的逆運算改寫成(1.25-0.75)x=1.8,即0.5x=1.8,再根據(jù)等式的性質(zhì),兩邊同除以0.5即可;
(2)把分?jǐn)?shù)化為小數(shù),根據(jù)等式的性質(zhì),兩邊同除以0.8即可.
點評:在解方程時應(yīng)根據(jù)等式的性質(zhì),即等式兩邊同加上、同減去或同乘上、同除以某一個數(shù)(0除外),等式的兩邊仍相等,同時注意“=”上下要對齊.