Đáp án:
Giải thích các bước giải:
`11)x^4y-5xy^3+2xy^3-5x^4y`
`=(x^4y-5x^4y)+(-5xy^3+2xy^3)`
`=-4x^4y-3xy^3`
`12)10x^3y^5-5xy+5x^3y^5+8xy`
`=(10x^3y^5+5x^3y^5)+(-5xy+8xy)`
`=15x^3y^5+3xy`
`13)-8x^2y^3+4x^3y^2-4x^3y^2+3x^2y^3`
`=(-8x^2y^3+3x^2y^3)+(4x^3y^2-4x^3y^2)`
`=-5x^2y^3`
`14)5xy^4-5xy+7xy-2xy^4`
`=(5xy^4-2xy^4)+(-5xy+7xy)`
`=2xy`
`15)3xy^2-7x^3y+5xy^2-2x^3y`
`=(3xy^2+5xy^2)+(-7x^3y-2x^3y)`
`=8xy^2-9x^3y`
`16)4x^3y+1/2x^3y`
`=(4+1/2)x^3y`
`=9/2 x^3y`
`17)1/5 x^4y^3-3x^4y^3`
`=(1/5-3)x^4y^3`
`=-14/5x^4y^3`
`18)5x^2y^5-1/4x^2y^5`
`=(5-1/4)x^2y^5`
`=19/4x^2y^5`
`19)3/4x^4y^7-3x^4y^7`
`=(3/4-3)x^4y^7`
`=-9/4x^4y^7`
`20)2/3x^3y^4+3x^3y^4`
`=(2/3+3)x^3y^4`
`=11/3x^3y^4`
