解方程．25x+45x=123.5x+1.8=12.335x÷2=14．

Question

解方程．
(2)/(5)x+(4)/(5)x=(1)/(2)
3.5x+1.8=12.3
(3)/(5)x÷2=(1)/(4)．

Answer 1

①(2)/(5)x+(4)/(5)x=(1)/(2)
         (6)/(5)x=(1)/(2)
      (6)/(5)x÷(6)/(5)=(1)/(2)÷(6)/(5)
          x=(5)/(12)
②3.5x+1.8=12.3
3.5x+1.8-1.8=12.3-1.8
        3.5x=10.5
   3.5x÷3.5=10.5÷3.5
           X=3
③(3)/(5)x÷2=(1)/(4)
(3)/(5)x÷2×2=(1)/(4)×2
      (3)/(5)x=(1)/(2)
   (3)/(5)x÷(3)/(5)=(1)/(2)÷(3)/(5)
       x=(5)/(6)