Чтобы дробь являлась натуральным числом, то член 3/n=к - должен быть целым
При к=1 получаем n=3 и это единственное число.
Ответ: При n= 3.
Вот : 2/3 х (1 + 2/3) = 3 1/5
2/3 х (5/3) = 3 1/5
2/3 х = 48/25
<span>х = 2, 88</span>
![(7-10)^3=(-3)^3=(-3)*(-3)*(-3)=-27](https://tex.z-dn.net/?f=%287-10%29%5E3%3D%28-3%29%5E3%3D%28-3%29%2A%28-3%29%2A%28-3%29%3D-27)
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![(6+(-10))*(6-(-10))=-4*16=-64](https://tex.z-dn.net/?f=%286%2B%28-10%29%29%2A%286-%28-10%29%29%3D-4%2A16%3D-64)
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![-\frac{8}{9}*(-\frac{27}{32})+\frac{23}{28}*(-\frac{49}{46})=\\\\\frac{3}{4}-\frac{49}{56}=\frac{3}{4}-\frac{7}{8}=\frac{6-7}{8}=-\frac{1}{8}](https://tex.z-dn.net/?f=-%5Cfrac%7B8%7D%7B9%7D%2A%28-%5Cfrac%7B27%7D%7B32%7D%29%2B%5Cfrac%7B23%7D%7B28%7D%2A%28-%5Cfrac%7B49%7D%7B46%7D%29%3D%5C%5C%5C%5C%5Cfrac%7B3%7D%7B4%7D-%5Cfrac%7B49%7D%7B56%7D%3D%5Cfrac%7B3%7D%7B4%7D-%5Cfrac%7B7%7D%7B8%7D%3D%5Cfrac%7B6-7%7D%7B8%7D%3D-%5Cfrac%7B1%7D%7B8%7D)
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![(4.5-6)*(1.8-(-3.4))=-1.5*5.2=-7.8](https://tex.z-dn.net/?f=%284.5-6%29%2A%281.8-%28-3.4%29%29%3D-1.5%2A5.2%3D-7.8)
1) (-21)(х+у)-3(х-у)
-21х-21у-3х+3у=-24х-18у.
2) -2n(2m-1)+(6-2n)(-m)
-4mn+2n-6m+2mn=-2mn+2n-6m.