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求未知数x.2x+1.5x=1.75;32.8-9x=1.75;2x+23×4=134;32-8x=28.4.

题目详情
求未知数x.
2x+1.5x=1.75;                            
32.8-9x=1.75;
2x+23×4=134;                           
32-8x=28.4.
▼优质解答
答案和解析
①2x+1.5x=1.75
    3.5x÷3.5=1.75÷3.5
            x=0.5;

②32.8-9x=1.75
  32.8-9x+9x=1.75+9x
1.75+9x-1.75=32.8-1.75
       9x÷9=31.05÷9
           x=3.45;

③2x+23×4=134
  2x+92-92=134-92
     2x÷2=42÷2
         x=21;

④32-8x=28.4
    32-8x+8x=28.4+8x
28.4+8x-28.4=32-28.4
       8x÷8=3.6÷8
           x=0.45.