Ta có:

Ta có:

A

Câu 10. A

4x³y(-2x²y³)(-xy³)=8x⁶y⁷

`4x^3 y (-2x^2y^3)(-xy^3)`

`=[4.(-2).(-1)].(x^3 .x^2 .x).(y.y^3 .y^3)`

`=8x^6y^7`

\(4x^3y\left(-2x^2y^3\right)\left(-xy^3\right)\)

\(=\left[4\cdot\left(-2\right)\right]\left[x^3\cdot x^2\cdot\left(-x\right)\right]\left(y\cdot y^3\cdot y^3\right)\)

\(=\left(-8\right)\left(-x\right)^6\left(y\right)^7\)

\(=-8x^6y^7\)

a: \(=\left(\dfrac{3}{4}+\dfrac{1}{2}-\dfrac{1}{4}\right)xyz^2=xyz^2\)

\(=-\dfrac{2}{5}.\dfrac{5}{4}.x^2.x^5.x^2.y^6.y^8=-\dfrac{1}{2}x^9y^{14}\)

Bậc của đa thức là: \(9+14=23\)

Hệ số là: \(-\dfrac{1}{2}\)

`( xy^3 )^2 . ( -2 / 5 x^5 ) . ( 5 / 4 x^2 y^8 )`

`= ( x^2 y^6 ) . ( -2 / 5 x^5 ) . ( 5 / 4 x^2 y^8 )`

`= ( -2 / 5 . 5 / 4 ) ( x^2 . x^5 . x^2 ) ( y^6 . y^ 8 )`

`= -1 / 2 x^9 y^14`

      `@` Bậc: `9 + 14 = 23`

      `@` Hệ số: `-1 / 2`

\(\left(xy^3\right)^2.\left(\dfrac{-2}{5}x^5\right).\left(\dfrac{5}{4}x^2y^8\right)\)

\(=\left(x^2y^6\right).\left(\dfrac{-2}{5}x^5\right).\left(\dfrac{5}{4}x^2y^8\right)\)

\(=\left(x^2.x^5.x^2\right).\left(y^6.y^8\right).\left(\dfrac{-2}{5}.\dfrac{5}{4}\right)\)

\(=x^9.y^{14}.\dfrac{-1}{2}\)

\(\text{Bậc là:23}\)

\(\text{Hệ số:}\dfrac{-1}{2}\)

a: M=(-2)*(-3)*x^3y*x^2y^3=6x^5y^4

Bậc là 9

Hệ số là 6

b: N=9x^4y^2*(-5)xy^3=-45x^5y^5

Bậc là 10

Hệ số là -45

Chọn D

a, \(3x^2y^3+x^2y^3=4x^2y^3\)

b, \(5x^2y-\dfrac{1}{2}x^2y=\dfrac{10-1}{2}x^2y=\dfrac{9}{2}x^2y\)

c, \(=\left(\dfrac{3}{4}+\dfrac{1}{2}-\dfrac{1}{4}\right)xyz^2=xyz^2\)