ĐKXĐ: `x\ne-4; x\ne -1;x\ne -6; x\ne 3`

`3/(x^2 +5x+4)+2/(x^2 +10x+24)=4/3+9/(x^2 +3x-18)`

`3/((x+1)(x+4))+2/((x+4)(x+6))=4/3 +9/((x-3)(x+6))`

`(x+4-(x+1))/((x+1)(x+4))+(x+6-(x+4))/((x+4)(x+6))-(x+6-(x-3))/((x-3)(x+6))=4/3`

`1/(x+1)-1/(x+4)+1/(x+4)-1/(x+6)-1/(x+3)+1/(x+6)=4/3`

`1/(x+1)-1/(x+3)=4/3`

`(x+3-x-1)/((x+1)(x+3))=4/3`

`2/((x+1)(x+3))=4/3`

`4(x+1)(x+3)=6`

`4(x^2 +4x+3)=6`

`4x^2 +16x+12=6`

`4x^2 +16x+6=0`

`4x^2 +16x+16-10=0`

`(2x+4)^2 =10`

`2x+4=\sqrt{10}` hoặc `2x+4=-\sqrt{10}`

`x=(\sqrt{10}-4)/2` (thỏa mãn) hoặc `x=(-\sqrt{10}-4}/2` (thỏa mãn)

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