номер 123 гдз 8 класс алгебра Муравин Муравин

1)\begin{equation}\frac{15}{x}+\frac{25}{x}=5 \end{equation}
15 + 25 = 5x
5x = 40
x = 8
ОДЗ: \begin{equation}x\neq 0 \end{equation}
2)\begin{equation}\frac{18}{x}-\frac{63}{x}=1,8 \end{equation}
18 - 63 = 1,8 · x
-45 = 1,8x \begin{equation}x=\frac{-45}{1,8} \end{equation}
x = 25
ОДЗ: \begin{equation}x\neq 0 \end{equation}
3)\begin{equation}\frac{9}{1,2x}-\frac{5}{x}=\frac{1}{6} \end{equation} \begin{equation}\frac{9}{1,2x}-\frac{5}{x}=\frac{1}{6} \end{equation}
45 - 30 = x
x = 15
ОДЗ: \begin{equation}x\neq 0 \end{equation}
4)\begin{equation}\frac{10}{1,6x}+\frac{5}{x}=\frac{9}{20} \end{equation} \begin{equation}\frac{10}{1,6x}+\frac{5}{x}=\frac{9}{20} \end{equation}
125 + 100 = 9x
225 = 9x \begin{equation}x=\frac{225}{9} \end{equation}
x = 25
ОДЗ: \begin{equation}x\neq 0 \end{equation}