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解方程.4.5×6+4x=41   7x-3.4x=0.72 2x+1.5x=42 &nb

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/14 19:50:29
解方程.
4.5×6+4x=41  
7x-3.4x=0.72
2x+1.5x=42   (x-4.5)×6=31.8
x÷1.2=8   (x+1.7)÷3=1.4.
(1)4.5×6+4x=41,
             27+4x=41,
          27+4x-27=41-27,
                4x=14,
             4x÷4=14÷4,
                 x=3.5;
(2)7x-3.4x=0.72,
        3.6x=0.72,
   3.6x÷3.6=0.72÷3.6,
           x=0.2;
(3)2x+1.5x=42,
        3.5x=42,
   3.5x÷3.5=42÷3.5,
           x=12;
(4)(x-4.5)×6=31.8,
            6x-27=31.8,
         6x-27+27=31.8+27,
               6x=58.8,
            6x÷6=58.8÷6,
                x=9.8;
(5)x÷1.2=8,
x÷1.2×1.2=8×1.2,
          x=9.6,
(6)(x+1.7)÷3=1.4,
  (x+1.7)÷3×3=1.4×3,
            x+1.7=4.2,
        x+1.7-1.7=4.2-1.7,
                x=2.5.