0, \ x^2-2x+8>0 \ \ x\in R; \\ (x+3)(x-1)(x^2-2x+8)\leq0, \\ (x+3)(x-1)\leq0, \\ x\in[-3;1]" alt="\frac{x^2+2x-3}{x^2-2x+8}\leq0, \\ \frac{x^2+2x-3}{x^2-2x+8}=0, \\ \left \{ {x^2+2x-3=0,} \atop {x^2-2x+8\neq0;}} \right. \\ 1) x_1=-3, x_2=1, x^2+2x-3=(x+3)(x-1); \\ 2) D/4=-7<0, \ x^2-2x+8\neq0, \\ a=1>0, \ x^2-2x+8>0 \ \ x\in R; \\ (x+3)(x-1)(x^2-2x+8)\leq0, \\ (x+3)(x-1)\leq0, \\ x\in[-3;1]" align="absmiddle" class="latex-formula">
\frac{1}{1-x}, \\ \frac{4-x}{x-5}-\frac{1}{1-x}>0, \\ \frac{(4-x)(1-x)-(x-5)}{(x-5)(1-x)}>0, \\ \frac{x^2-6x+9=0}{(x-5)(1-x)}>0, \\ \frac{x^2-6x+9=0}{(x-5)(1-x)}=0, \\ x^2-6x+9=0, (x-3)^2=0, x-3=0, x=3, \\ (x-5)(1-x)\neq0, \\ x-5\neq0, x\neq5, \\ 1-x\neq0, x\neq1, \\ (x-3)^2(x-5)(1-x)>0, \\ (x-3)^2>0, x\in R, \\ (x-5)(1-x)>0, \\ (x-5)(x-1)<0, \\ x\in(1;3)\cup(3;5)" alt="\frac{4-x}{x-5}>\frac{1}{1-x}, \\ \frac{4-x}{x-5}-\frac{1}{1-x}>0, \\ \frac{(4-x)(1-x)-(x-5)}{(x-5)(1-x)}>0, \\ \frac{x^2-6x+9=0}{(x-5)(1-x)}>0, \\ \frac{x^2-6x+9=0}{(x-5)(1-x)}=0, \\ x^2-6x+9=0, (x-3)^2=0, x-3=0, x=3, \\ (x-5)(1-x)\neq0, \\ x-5\neq0, x\neq5, \\ 1-x\neq0, x\neq1, \\ (x-3)^2(x-5)(1-x)>0, \\ (x-3)^2>0, x\in R, \\ (x-5)(1-x)>0, \\ (x-5)(x-1)<0, \\ x\in(1;3)\cup(3;5)" align="absmiddle" class="latex-formula">