`A=((-3)/4x^5y^4).(xy^2).((-8)/9x^2y^5)`
`=((-3)/4.(-8)/9).(x^5.x.x^2)(y^4.y^2.y^5)`
`=2/3x^8y^11`
$\text{⇒ Bậc: 19}$
`B=3x^5y+1/3xy^4+3/4x^2y^3-1/2x^5y+2xy^4-x^2y^3`
`=(3x^5y-1/2x^5y)+(1/3xy^4+2xy^4)+(3/4x^2y^3-x^2y^3)`
`=5/2x^5y+7/3xy^4-1/4x^2y^3`
$\text{⇒ Bậc: 6}$