1,4 * (3 - 2b) + 0,7b - 8,2 = 4,2 - 2,8b + 0,7b - 8,2 = -2,1b - 4 = -(2,1b + 4),
при b = -3/16: <span>-(2,1b + 4) = -(2,1 * (-3/16) + 4) = -(21/10*(-3/16) + 4) = 63/160 - 4 = -3 97/160</span>
1. на 4: 6и10, 13 и 17, 40и36, 19 и 5
2. нет таких
0,5=1,0 3,7=4,0
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25 х - 5 х = 420
20 х = 420
х= 420 : 20
х= 21