解方程或解比例.(1)X-15×3=120 &n...

解方程或解比例.(1)X-15×3=120 (2)15:X=7.5:20.
2025-06-26 14:03:57
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回答1:

(1)X-15×3=120,
            x-45=120,
         x-45+45=120+45,
               x=165;

(2)15:X=7.5:20,
      7.5x=15×20,
 7.5x÷7.5=300÷7.5,
         x=40.