1) D = 4(-xy3)2x = -4x3y6
=> bậc của D là: 3 + 6 = 9
2) C.D = (-3x3y6).(-4x3y6) = 12x6y12
`1)`
`D=4(-xy^3)^2x`
`D=4(x^2y^6)x`
`D=4x^3y^6`
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`2)C.D=(-3x^3y^6).(4x^3y^6)`
`=(-3.4)(x^3 .x^3)(y^6 .y^6)`
`=-12x^6y^12`