\(=\left[7\left(4x^2-25y^2-4x+10y\right)\left(14x^2-3y^2\right):\left(-3y\right)\right]\)

\(=\dfrac{7\left(56x^2-362x^2y^2+75y^4-56x^3+12xy^2-140x^2y-30y^3\right)}{-3y}\)

\(=\dfrac{7\left(56x^2-362x^2y^2+75y^4-56x^3+12xy^2-140x^2y-30y^3\right)}{-3y}\)

\(=\dfrac{-392x^2}{3y}+\dfrac{2534}{3}x^2y-175y^3+\dfrac{392}{3}x^3:y-28xy+\dfrac{980}{3}x^2+70y^2\)

\(A=4x^2+12xy+9y^2\)

\(B=25x^2-10xy+y^2\)

\(C=8x^3+12x^2y^2+6xy^4+y^6\)

\(D=\left(x^2\right)^2-\left(\dfrac{2}{5}y\right)^2=x^4-\dfrac{4y^2}{25}\)

\(E=x^3-27y^3\)

\(F=x^6-27\)

a) (x + 3y) (2x²y - 6xy²)

= (x + 3y) + 2xy (x - 3y)

= 2xy [(x + 3y) (x - 3y)]

= 2xy (x² - 3y²)

b) (6x⁵y² - 9x⁴y³ + 15x³y⁴) : 3x³y²

= (6x⁵y² : 3x³y²) + (-9x⁴y³ : 3x³y²) + (15x³y⁴ : 3x³y²)

= [(6 : 3) (x⁵ : x³) (y² : y²)] + [(-9 : 3) (x⁴ : x³) (y³ : y²)] + [(15 : 3) (x³ : x³) (y⁴ : y²)]

= 2x² + (-3xy) + 5y²

= 2x² - 3xy + 5y²

#Học tốt!!!

a: \(=\dfrac{6}{3}\cdot x\cdot\dfrac{y^2}{y}=2xy\)

b: \(=\dfrac{62}{2}\cdot\dfrac{x^4}{x^3}\cdot\dfrac{y^3}{y^2}=31xy\)

c: \(=\dfrac{-18}{6}\cdot\dfrac{x^4}{x^2}\cdot\dfrac{y^3}{y}=-3x^2y^2\)

d: \(=\dfrac{27}{9}\cdot\dfrac{x^5}{x^3}\cdot\dfrac{y^6}{y^3}=3x^2y^3\)

e: \(=\dfrac{18}{12}\cdot\dfrac{x^3}{x}\cdot\dfrac{y^4}{y^3}=\dfrac{3}{2}x^2y\)

a: \(=2x^{5-n}-x^{3-n}+\dfrac{2}{7}x^{1-n}\)

Để đây là phép chia hết thì 1-n>=0

hay n<=1

b: \(=\dfrac{-25}{3}x^{7-n}y^{6-n}+\dfrac{10}{3}x^{5-n}y^{4-n}+2x^{3-n}y^{2-n}\)

Để đây là phép chia hét thì 2-n>=0

hay n<=2