解方程．2.64+3x=15.3x+3.78=7.682x-0.5×2=0.83x-8=283x-45=10.56y=11.4x÷0.5=494.2x-2.7x=4.5．

Question

解方程．
2.64+3x=15.3      x+3.78=7.68      2x-0.5×2=0.8       3x-8=28
3x-45=10.5         6y=11.4          x÷0.5=49          4.2x-2.7x=4.5．

Answer 1

①2.64+3x=15.3
 2.64+3x-2.64=15.3-2.64
           3x=12.66
        3x÷3=12.66÷3
            x=4.22

   ②x+3.78=7.68 
x+3.78-3.78=7.68-3.78
          x=3.9

③2x-0.5×2=0.8     
     2x-1+1=0.8+1
         2x=1.8
      2x÷2=1.8÷2
          x=0.9

④3x-8=28
3x-8+8=28+8
    3x=36
 3x÷3=36÷3
     x=12

 ⑤3x-45=10.5 
3x-45+45=10.5+45
      3x=55.5 
   3x÷3=55.5÷3
       x=18.5

 ⑥6y=11.4 
6y÷6=11.4÷6
    x=1.9

   ⑦x÷0.5=49 
x÷0.5×0.5=49×0.5
          x=24.5

⑧4.2x-2.7x=4.5
       1.5x=4.5
  1.5x÷1.5=4.5÷1.5
          x=3