Question

Thực hiện phép tính:

f) \((\dfrac{2}{3}x^2-\dfrac{1}{2}y)^3\)

Answer 1

f, \(\left(\dfrac{2}{3}x^2-\dfrac{1}{2}y\right)^3\)

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

\(=\dfrac{8}{27}x^5-3.\dfrac{4}{9}x^4.\dfrac{1}{2}y+2x^2.\dfrac{1}{4}y^2-\dfrac{1}{8}y^3\)

\(=\dfrac{8}{27}x^5-\dfrac{2}{3}x^4y+\dfrac{1}{2}x^2y^2-\dfrac{1}{8}y^3\)

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