Автор - ghfhffhf
231 + х = 909 : 3
231 + х = 303
х = 303 - 231
х = 72
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75 : х = 50 : 10
75 : х = 5
х = 75 : 5
х = 15
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20 * а - 432 = 568
20а = 568 + 432
20а = 1000
а = 1000 : 20
а = 50
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х + 579 = 309 * 3
х + 579 = 927
х = 927 - 579
х = 348
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х - 465 = 76 * 5
х - 465 = 380
х = 380 + 465
х = 845