: (-3; 1) ; {2}
ax^2+bx+c=a(x-x1)(x-x2), x^2+2x-3=(x-1)(x+3) где x=1 u x=-3 корни
x/(x+3) - 3/(x-1) + 13/(x-1)(x+3) <=0, (x^2-x-3x-9+13)/(x-1)(x+3)<=0
(x^2-4x+4)/(x-1)(x+3) <=0, (x-2)^2 /(x-1)(x+3) <=0
+ + + + + + (-3) - - - - - - -(1) + + + + + + +[2] + + + + + +
: (-3; 1) u 2