Question

12. 8
------- - -------=1

X-1. X+1

X+15. 21
-------- - ---------=2
4. X+2
Радцонал

Answer 1

$\frac{12}{x-1} - \frac{8}{x+1} =1|\cdot (x-1)(x+1) \\ 12(x+1)-8(x-1)=(x-1)(x+1) \\ 12x+12-8x+8=x^2-1 \\ x^2-4x-21=0$
По т. ВИета:
$\left \{ {{x_1+x_2=4} \atop {x_1\cdot x_2=-21}} \right. \to \left \{ {{x_1=7} \atop {x_2=-3}} \right.$

Ответ: -3 и 7.

$\frac{x+15}{4} - \frac{21}{x+2} =2|\cdot 4(x+2) \\ (x+15)(x+2)-21\cdot 4=8(x+2) \\ x^2+17x+30-84=8x+16 \\ x^2+9x-70=0$
По т. Виета:
$\left \{ {{x_1+x_2=-9} \atop {x_1\cdot x_2=-70}} \right. \to \left \{ {{x_1=-14} \atop {x_2=5}} \right.$

Ответ: -14 и 5.