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解方程:x-6.75=1.680.7x=4.212-3ⅹ=60.7x+6×5=37(10x-25)÷5=157.9X-X=8.97.

题目详情
解方程:
x-6.75=1.68                  
0.7x=4.2                
12-3ⅹ=6 0.7x+6×5=37               
(10x-25)÷5=15           7.9X-X=8.97.
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答案和解析
(1)x-6.75=1.68
   x-6.75+6.75=1.68+6.75
             x=8.43;

(2)0.7x=4.2 
0.7x÷0.7=4.2÷0.7
        x=6; 

(3)12-3ⅹ=6
12-3ⅹ+3x=6+3x
     6+3x=12
   6+3x-6=12-6
       3x=6
        x=2;

(4)0.7x+6×5=37
     0.7x+30=37                        
  0.7x+30-30=37-30
        0.7x=7
           x=10;

(5)(10x-25)÷5=15
  (10x-25)÷5×5=15×5
          10x-25=75                               
       10x-25+25=75+25
             10x=100
         10x÷10=100÷10
               x=10;      

(6)7.9X-X=8.97 
     6.9X=8.97
6.9X÷6.9=8.97÷6.9
        X=1.3.