8 1/6 : (-1/2 - 2/3) + 5 · 1 2/9 = - 8/9
1) - 1/2 - 2/3 = - (3/6 + 4/6) = - 7/6
2) 8 1/6 : (-7/6) = 49/6 · (-6/7) = - 49/7 = - 7
3) 5 · 1 2/9 = 5 · 11/9 = 55/9 = 6 1/9
4) - 7 + 6 1/9 = - (7 - 6 1/9) = - (6 9/9 - 6 1/9) = - 8/9
5а*16b=80ab
..................
P=(a+b)*2
17см=а
х=b
17+x=56:2
17+x=28
x=11cм-вторая сторона.
2000- 100\%
20-1\%
600-30\%
2000:100•30=600
2000-600=1400
ответ:1400