41,5−(19)−0,5+(164)−23=41,5−19−0,5+164−23=22,5-0,5+164-23=22+164-23=186-23=163
X - скорость пешком, значит x+8 = скорость на велосипеде
3x + 2(x+8) = 36
3x + 2x + 16 = 36
5x + 16 = 36
5x = 20
x=4
Турист шел со скорость 4 км/ч
Геом прогрессия с первым членом 5/3, знаменателем 1/3
Сумма (по формуле):
![S=\dfrac{a_1}{1-q}=\dfrac{5/3}{2/3}=5/2](https://tex.z-dn.net/?f=S%3D%5Cdfrac%7Ba_1%7D%7B1-q%7D%3D%5Cdfrac%7B5%2F3%7D%7B2%2F3%7D%3D5%2F2)
![(a+b)^5=a^5+5a^4b+10a^3b^2+10a^2b^3+5ab^4+b^5](https://tex.z-dn.net/?f=%28a%2Bb%29%5E5%3Da%5E5%2B5a%5E4b%2B10a%5E3b%5E2%2B10a%5E2b%5E3%2B5ab%5E4%2Bb%5E5)
![(2a-1/5)^5=32a^5-16a^4+\frac{8}{5}a^3-\frac{4}{25}a^2+\frac{2}{125}a-\frac{1}{3125}](https://tex.z-dn.net/?f=%282a-1%2F5%29%5E5%3D32a%5E5-16a%5E4%2B%5Cfrac%7B8%7D%7B5%7Da%5E3-%5Cfrac%7B4%7D%7B25%7Da%5E2%2B%5Cfrac%7B2%7D%7B125%7Da-%5Cfrac%7B1%7D%7B3125%7D)
1). x² = 10 x₁ = √10 x₂ = -√10
2). x² = 20 x₁ = 2√5 x₂ = -2√5
3). x² = 18 x₁ = 3√2 x₂ = -3√2
4). x² = 121 x₁ = 11 x₂ = -11
5). x² = 490 x₁ = 7√10 x₂ = -7√10
6). x² = 1000 x₁ = 10√10 x₂ = -10√10
7). x² = 4000 x₁ = 20√10 x₂ = -20√10