问题 解答题
解方程.
①15+5X=25②5X-1.8X=24③3(X+2.1)=10.5.
答案

①15+5X=25

15+5X-15=25-15,

5x=10,

5x÷5=10÷5,

x=2;

②5X-1.8X=24,

3.2x=24,

3.2x÷3.2=24÷3.2,

x=7.5;

③3(X+2.1)=10.5,

3(X+2.1)÷3=10.5÷3,

x+2.1-2.1=3.5-2.1,

x=1.4.

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