Ta có: \(\dfrac{2}{3}x^2yz\cdot\left(-3xy^2\right)\)

\(=\left(-\dfrac{2}{3}\cdot3\right)\cdot\left(x^2\cdot x\right)\cdot\left(y\cdot y^2\right)\cdot z\)

\(=-2x^3y^3z\)

`(2/3x^2.y.z).(-3x.y^2)`

`=-3.(2/3).x^2.y.z.x.y^2`

`=-1.x^{2+1}.y^{2+1}.z`

`=-x^3y^3z`

-2 nha ghi nhầm ._.

\(\left(-2x^2y^2z\right).\left(-\dfrac{1}{3}x^2y^3\right)\)

\(=-2.x^2.y^2.z^2.\dfrac{-1}{3}.x^2.y^3\)

\(=\dfrac{2}{3}x^4y^5z^2\)

Ta có: \(-2x^2y^2z\cdot\dfrac{-1}{3}x^2y^3\)

\(=\left(-2\cdot\dfrac{-1}{3}\right)\cdot\left(x^2\cdot x^2\right)\cdot\left(y^2\cdot y^3\right)\cdot z\)

\(=\dfrac{2}{3}x^4y^5z\)

`(-2.x^2.y^2.z).(-1/3.x^2.y^3)`

`=-2/3.x^{2+2}.y^{2+3}.z`

`=-2/3x^4y^5x`

giup em vs

a, P=-3(x^3.x)(y^2.y^3)

      =-3x^4y^5

b, Thay x=-1 , y=2 vào đơn thức P . Ta có :

P=-3.(-1)^4.2^5

P=3.1.32

P=96

Đề sai rồi bạn

(1)

a)\(-\dfrac{3}{8}x^2yz\) \(\Rightarrow\)bậc là 2

b)5x \(\Rightarrow\)bậc là 1

c)0,26 =>bậc là 0

d)-3yz⁶ => bậc là 6

(2)

1 biến:5x¹⁰

2 biến:3x¹⁰y

3 biến:7xyz¹⁰

đề bài?

\(\left(-x^3.z.y\right).\left(\dfrac{2}{3}.y.x^2\right)^2\)

\(=-x^3.z.y.\dfrac{4}{9}.y^2.x^4\)

\(=-\dfrac{4}{9}x^7.y^3.z\)

`(-x^3zy)(2/3yx^2)^2`

`=-4/9x^3zy.y^2x^4`

`=-4/9x^{3+4}.y^{1+2}z`

`=-4/9x^7y^3z`

\(\left(-x^3zy\right)\left(\dfrac{2}{3}yx^2\right)^2\)

\(\Leftrightarrow\left(-x^3yz\right)\left(\dfrac{2}{3}x^2y\right)\left(\dfrac{2}{3}x^2y\right)\)

\(\Leftrightarrow-\left[x^7y^3z\left(\dfrac{2}{3}\right)^2\right]\)

\(\Leftrightarrow-\dfrac{4}{9}x^7y^3z\)