x-3≠0
x+1≠0 Это область допустимых значений.
![\frac{x-3}{x+1}=a\\a+1/a=26/5\\a^2+1-26a/5=0\\a^2/2-13a/5+1/2=0\\D=169/25-1=144/25\\a=13/5б12/5=\left[\begin{array}{ccc}1/5\\5\\\end{array}](https://tex.z-dn.net/?f=%5Cfrac%7Bx-3%7D%7Bx%2B1%7D%3Da%5C%5Ca%2B1%2Fa%3D26%2F5%5C%5Ca%5E2%2B1-26a%2F5%3D0%5C%5Ca%5E2%2F2-13a%2F5%2B1%2F2%3D0%5C%5CD%3D169%2F25-1%3D144%2F25%5C%5Ca%3D13%2F5%D0%B112%2F5%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%2F5%5C%5C5%5C%5C%5Cend%7Barray%7D)
![\left[\begin{array}{ccc}\frac{x-3}{x+1}=0.2\\\frac{x-3}{x+1}=5\\\end{array}](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%5Cfrac%7Bx-3%7D%7Bx%2B1%7D%3D0.2%5C%5C%5Cfrac%7Bx-3%7D%7Bx%2B1%7D%3D5%5C%5C%5Cend%7Barray%7D)
![\left[\begin{array}{ccc}x-3=0.2x+0.2\\x-3=5x+5\\\end{array}](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx-3%3D0.2x%2B0.2%5C%5Cx-3%3D5x%2B5%5C%5C%5Cend%7Barray%7D+)
![\left[\begin{array}{ccc}0.8x=3.2\\-8=4x\\\end{array}](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0.8x%3D3.2%5C%5C-8%3D4x%5C%5C%5Cend%7Barray%7D+)
![\left[\begin{array}{ccc}x=4\\x=-2\\\end{array}](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%3D4%5C%5Cx%3D-2%5C%5C%5Cend%7Barray%7D+)
Проверяем на ОДЗ: x≠3 и x≠-1
Ответ: x={-2;4}
U1 - скорость первого
u1+3 - скорость второго
180/u1 - 180/(u1+3) = 2
180(u1+3) - 180u1 = 2u1 *(u1+3)
540 = 2u1^2 + 6u1
u1^2 + 3u1 - 270 = 0
u1 = 15 км/ч
(a+3)^2-19, (x-2)^2-3, (c+5)^2-25
Это параллель.
например: линия а | | линии б (а параллейно б)