Задача 45389 ...

sova

2020-03-26 13:29:20

★

a)
[m]6\cdot\frac{(5x-9)`}{5x-9}=3\cdot \frac{(7-5x)`}{7-5x}[/m]

[m]6\cdot\frac{5}{5x-9}=3\cdot \frac{(-5)}{7-5x}[/m]

[m]2\cdot\frac{1}{5x-9}=-\cdot \frac{1}{7-5x}[/m]

2*(7-5x)=5x-9

14-10x=5x-9

-10x-5x=-14-9

15x=23

x=[m]\frac{23}{15}[/m]

б)
[m]-\frac{1}{sin^2x}=2[/m]

[m]sin^2x=-\frac{1}{2}[/m] - уравнение не имеет корней,


sin^2x ≥ 0