Đáp án + Giải thích các bước giải:
`g)` `(x^5+x^3+x^2+1)/(x^3+x^2+x+1) ( x ne -1)`
`=[x^3(x^2+1)+(x^2+1)]/[x^2(x+1)+(x+1)]`
`=[(x^2+1)(x^3+1)]/[(x+1)(x^2+1)]`
`=[(x^2+1)(x+1)(x^2-x+1)]/[(x+1)(x^2+1)]=x^2-x+1`
`h)` `(x^3y+xy^3+xy)/(x^3+y^3+x^2y+xy^2+x+y) (x ne -y)`
`=[xy(x^2+y^2+1)]/[(x+y)(x^2-xy+y^2)+xy(x+y)+(x+y)]`
`=[xy(x^2+y^2+1)]/[(x+y)(x^2-xy+y^2+xy+1)]`
`=[xy(x^2+y^2+1)]/[(x+y)(x^2+y^2+1)]=(xy)/(x+y)`
`i)` `(x^4-1)/(x^3+2x^2-x-2) (x ne -2,x ne pm1)`
`=[(x^2)^2-1^2]/[x^2(x+2) - (x+2)]`
`=[(x^2-1)(x^2+1)]/[(x+2)(x^2-1)]`
`=(x^2+1)/(x+2)`
`k)` `(x^2+7x+12)/(x^2+5x+6) (x ne -2,x ne -3)`
`=(x^2+3x+4x+12)/(x^2+2x+3x+6)`
`=[x(x+3)+4(x+3)]/[x(x+2)+3(x+2)]`
`=[(x+3)(x+4)]/[(x+2)(x+3)]=(x+4)/(x+2)`.
