0,8 * х - 2,6 * х = 1
х * (0,8 - 2,6) = 1
х * (-1,8) = 1
х = 1 : (-1,8) = - 10/18 (сократим на 2)
х = - 5/9
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Проверка: - (0,8*5)/9 + (2,6*5)/9 = 1
- 4/9 + 13/9 = 1
9/9 = 1
№1
1) (60+5)+(30+2)+(5+2)=90+7=97
2) (20+3)+(40+2)+(3+2)=60+5=65
3) (30+4)+(50+5)+(4+5)=80+9=89
4) (40+6)+(50+3)+(6+3)=90+9=99
5) (10+7)+(70+1)+(7+1)=80+8=88
6) (20+3)+(40+4)+(3+4)=60+5=65
№2
46 62 46 28 54 26 75 43
+ + + + + + + +
33 26 53 41 14 35 21 43
= = = = = = = =
79 88 99 69 68 61 96 86
№3
1) 55=55
2) 91 ≤97
3)89≥88
4) 68=68