Решение по действиям:
1) 5 1/8 - 2 1/4 = 5 1/8 - 2 2/8 = 2 + (9/8 - 2/8) = 2 7/8
2) 3 7/16 - 1 1/8 = 3 7/16 - 1 2/16 = 2 5/16
3) 2 7/8 + 2 5/16 = 2 14/16 + 2 5/16 = 4 19/16 = 5 3/16
1999,2000,2001,2002,2003,2004
-2x^2+x^2+<span>x^2+x-5x=-7-2
-4x=-9
4x=9
x=9/4</span>
100-19=81
81:3=27
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