5. (5x–7) (8x + 1) = (7-5x).

Решим уравнение:

1. $$(5x - 7)(8x + 1) = 7 - 5x$$ $$40x^2 + 5x - 56x - 7 = 7 - 5x$$ $$40x^2 - 51x - 7 = 7 - 5x$$ $$40x^2 - 51x + 5x - 7 - 7 = 0$$ $$40x^2 - 46x - 14 = 0$$ $$20x^2 - 23x - 7 = 0$$

2. Найдем дискриминант:

   $$D = b^2 - 4ac = (-23)^2 - 4 \cdot 20 \cdot (-7) = 529 + 560 = 1089$$

3. Найдем корни:

   $$x_1 = \frac{-b + \sqrt{D}}{2a} = \frac{23 + \sqrt{1089}}{2 \cdot 20} = \frac{23 + 33}{40} = \frac{56}{40} = \frac{7}{5} = 1.4$$ $$x_2 = \frac{-b - \sqrt{D}}{2a} = \frac{23 - \sqrt{1089}}{2 \cdot 20} = \frac{23 - 33}{40} = \frac{-10}{40} = -\frac{1}{4} = -0.25$$

Ответ: x = 1.4, x = -0.25