Đáp án+Giải thích các bước giải:
`10) (10x+11)/(3x-3)+(15x+13)/(4-4x^2)`
`=(10x+11)/(3(x-1))-(15x+13)/(4(x^2-1))`
`=(4(x+1)(10x+11))/(12(x^2-1))-(3(15x+13))/(12(x^2-1))`
`=((4x+4)(10x+11)-45x-39)/(12(x^2-1))`
`=(40x^2+44x+40x+44-45x-39)/(12(x^2-1))`
`=(40x^2+39x+5)/(12(x^2-1))`
`11) 1/(x+3)+4/(3x^2+14x+15)`
`=1/(x+3)+4/((3x+5)(x+3))`
`=(3x+5)/((3x+5)(x+3))+4/((3x+5)(x+3))`
`=(3x+5+4)/((3x+5)(x+3))`
`=(3x+9)/((3x+5)(x+3))`
`=(3(x+3))/((3x+5)(x+3))`
`=3/(3x+5)`
`12) (6x)/(x^3+1)+1/(x^2-x+1)+2/(x+1) (ĐKXĐ: x \ne-1)`
`=(6x)/(x^3+1)+(x+1)/(x^3+1)+(2(x^2-x+1))/(x^3+1)`
`=(6x+x+1+2x^2-2x+2)/(x^3+1)`
`=(2x^2+5x+3)/(x^3+1)`
`=((x+1)(2x+3))/(x^3+1)`
`=(2x+3)/(x^2-x+1)`