Question

Bài 2. Thực hiện phép tính a) 1/2 xy^2 × ( 6xy + 3/2 x^3y - 1

b) ( 2x - 1/2y ) × ( 2x + 1/2y )

c) 24x^5y^3z^6 ÷ 6x^4y^2z^3

d) ( 3x^6y^7z^6 + 2x^5y^3z^7 - 6x^5y^3z^8 ) ÷ 42x^3y^3z^6

Giúp mik với ạ

Answer 1

a: \(\dfrac{1}{2}xy^2\left(6xy+\dfrac{3}{2}x^3y-1\right)\)

\(=\dfrac{1}{2}xy^2\cdot6xy+\dfrac{1}{2}xy^2\cdot\dfrac{3}{2}x^3y-\dfrac{1}{2}xy^2\cdot1\)

\(=3x^2y^3+\dfrac{3}{4}x^4y^3-\dfrac{1}{2}xy^2\)

b: \(\left(2x-\dfrac{1}{2}y\right)\left(2x+\dfrac{1}{2}y\right)=\left(2x\right)^2-\left(\dfrac{1}{2}y\right)^2=4x^2-\dfrac{1}{4}y^2\)

c: \(24x^5y^3z^6:6x^4y^2z^3\)

\(=\left(\dfrac{24}{6}\right)\cdot\dfrac{x^5}{x^4}\cdot\dfrac{y^3}{y^2}\cdot\dfrac{z^6}{z^3}\)

\(=4xyz^3\)

d: \(\dfrac{3x^6y^7z^6+2x^5y^3z^7-6x^5y^3z^8}{42x^3y^3z^6}\)

\(=\dfrac{3x^6y^7z^6}{42x^3y^3z^6}+\dfrac{2x^5y^3z^7}{42x^3y^3z^6}-\dfrac{6x^5y^3z^8}{42x^3y^3z^6}\)

\(=\dfrac{1}{14}x^3y^4+\dfrac{1}{21}x^2z-\dfrac{1}{7}x^2z^2\)