Giúp mình với!

`5.`

        `(2x^3y -5xy^3):3xy=B-5/3y^2`

`⇔2/3x^2 -5/3y^2=B-5/3y^2`

`⇔B=2/3x^2 -5/3y^2+ 5/3y^2`

`⇔B=2/3x^2`

Vậy, `B=2/3x^2`

`6.`

        `(4x^4y4 -5/4x^5y^5):3x^2y^2=B-5/12x^3y^3`

`⇔4/3x^2y^2 - 5/12x^3y^3 =B-5/12x^3y^3`

`⇔B=4/3x^2y^2 - 5/12x^3y^3+ 5/12x^3y^3`

`⇔B=4/3x^2y^2`

Vậy, `B=4/3x^2y^2`

___

Nếu đề là:

        `(4x^4y4 -5/4x^5y^5):3x^2y^2=B-5/12x^3y`

`⇔4/3x^2y^2 - 5/12x^3y^3 =B-5/12x^3y`

`⇔B=4/3x^2y^2 - 5/12x^3y^3+ 5/12x^3y`

Vậy, `B=4/3x^2y^2 - 5/12x^3y^3+ 5/12x^3y`

`#` $kiddd$