GIÚP MIK VS Ạ MIK CẦN GẤP!!!!

`a) A=5xy-3,5y^2-2x1,3y^2-xy`

`=(5xy-2xy)+(3,5y^2+1,3y^2)+(-2xy-xy)`

`=3xy+4,8y^2-3xy`

`b) B=1/2xb^2-7/ab^2+3/4a^2b-3/8a^2b-1/2ab^2`

`=1/2xb^2+(-7/8ab^2-1/2ab^2)+(3/4a^2b-3/8a^2b)`

`=1/2xb^2-11/8ab^2+3/8a^2b`

`c) C=3ab-2bc+4ac-ab+3bc+4ab`

`=(3ab-ab+4ab)+(-2bc+3bc)+4ac`

`=6ab+1bc+4ac`

`d)D=-2x^3+xy^2+x^2y-1+x^2y-xy^2+3x^2`

`=(-2x^3+3x^3)+(xy^2-xy^2)+(x^2y+x^2y)-1`

`=x^3+2x^2y-1`