Question

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Answer 1

Bài 1

a) \(\dfrac{7xy}{3x+1}.\dfrac{6x+2}{14x^2y}\)

\(=\dfrac{7xy}{3x+1}.\dfrac{2\left(3x+1\right)}{7xy.2x}\)

\(=\dfrac{1}{x}\)

b) \(\dfrac{3x-1}{10x^2+2x}.\dfrac{25x^2+10x+1}{1-9x^2}\)

\(=\dfrac{3x-1}{2x\left(5x+1\right)}.\dfrac{\left(5x+1\right)^2}{-\left(3x-1\right)\left(1+3x\right)}\)

\(=\dfrac{-5x-1}{2x\left(1+3x\right)}\)

Answer 2

Bài 2

a) \(\dfrac{-25}{14xy^2}:\dfrac{15y^3}{21x}\)

\(=\dfrac{-25}{14xy^2}.\dfrac{21x}{15y^3}\)

\(=\dfrac{-5.5}{7x.2y^3}.\dfrac{7x.3}{5.3y^3}\)

\(=\dfrac{-5}{2y^3.y^3}\)

\(=\dfrac{-5}{2y^6}\)

b) \(\dfrac{9xy^2}{10x+4}:\dfrac{-3}{5x+2}\)

\(=\dfrac{9xy^2}{10x+4}.\dfrac{5x+2}{-3}\)

\(=\dfrac{3.3xy^2}{2\left(5x+2\right)}.\dfrac{5x+2}{-3}\)

\(=\dfrac{-3xy^2}{2}\)