`(5x)/(x^2-x-6) + x/(3-x) = 2/(x+2) - 1` ` (x\ne-2; x\ne3)`
`<=>(5x)/(x^2+2x-3x-6) + x/(3-x) = 2/(x+2) - 1`
`<=>(5x)/(x(x+2)-3(x+2)) + x/(3-x) = 2/(x+2) - 1`
`<=>(5x)/((x-3)(x+2))-x/(x-3)=2/(x+2)-1`
`<=>(5x)/((x-3)(x+2))-(x(x+2))/((x-3)(x+2))=(2(x-3))/((x-3)(x+2))-((x-3)(x+2))/((x-3)(x+2))`
`<=>(5x-x(x+2))/((x-3)(x+2))=(2(x-3)-(x-3)(x+2))/((x-3)(x+2))`
`=>5x-x(x+2)=2(x-3)-(x-3)(x+2)`
`<=>5x-x^2-2x=2x-6-x^2-2x+3x+6`
`<=> 5x -2x -2x+2x-x^2+x^2-3x=-6+6`
`<=>0x=0` (Luôn đúng với `∀x∈R`)
Vậy: `S∈R` ` (x\ne-2; x\ne3)`