1. \(A=2xy\left(xy\right)=2x.x.y.y=2x^2y^2\)
\(B=2x^2y\left(-\dfrac{1}{2}xy\right)x^2y=2\cdot\left(-\dfrac{1}{2}\right)\cdot x^2.x.x^2.y.y.y=-x^5y^3\)
\(C=\dfrac{8}{7}xy\left(3xy\right)=\dfrac{8}{7}\cdot3.x.x.y.y=\dfrac{24}{7}x^2y^2\)
\(D=-2\dfrac{1}{3}x^3z^2\left(\dfrac{1}{7}xy^2z\right)^2=-\dfrac{7}{3}x^3z^2\left(\dfrac{1}{49}x^2y^4z^2\right)\)
\(=-\dfrac{7}{3}\cdot\dfrac{1}{49}\cdot x^3.x^2.y^4.z^2.z^2=-\dfrac{1}{21}x^5y^4z^4\)
\(E=y^2x^2\left(-\dfrac{1}{2}xy^2z\right)^2=y^2x^2\left(-\dfrac{1}{4}x^2y^4z^2\right)\)
\(=-\dfrac{1}{4}x^2.x^2.y^2.y^4.z^2=-\dfrac{1}{4}x^4y^6z^2\)
2.1. \(\dfrac{1}{5}xy^2z\left(-5xy\right)=-x^2y^3z\). Hệ số : \(-1.\) Phần biến : \(x^2y^3z.\)
2.2. \(x^3\left(-\dfrac{1}{3}y\right)\dfrac{1}{5}y^2y=-\dfrac{1}{15}x^3y^4\). Hệ số : \(-\dfrac{1}{15}.\) Phần biến : \(x^3y^4.\)
2.3. \(\dfrac{2}{3}x^2y^3z\left(-x^3yz\right)=-\dfrac{2}{3}x^5y^4z^2.\) Hệ số : \(-\dfrac{2}{3}.\) Phần biến : \(x^5y^4z^2.\)
2.4. \(-ax\left(xy^3\right)\dfrac{1}{4}\left(-by\right)^3=\dfrac{1}{4}ab^3x^2y^6.\) Hệ số : \(\dfrac{1}{4}ab.\) Phần biến : \(x^2y^6.\)
