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20 tháng 11 2018

\(\frac{1}{6x^2y^3}=\frac{7x^2}{42x^4y^3},\frac{-5}{21xy^2}=\frac{-10x^3y}{42x^4y^3},\frac{3}{14x^4y}=\frac{3y^2}{14x^4y^3}\)

\(\dfrac{1}{6x^2y^3}=\dfrac{7x^2}{42x^4y^3};\dfrac{-5}{21xy^2}=\dfrac{-10x^3y}{42x^4y^3};\dfrac{3}{14x^4y}=\dfrac{9y^2}{42x^4y^3}\)

20 tháng 11 2022

a: \(\dfrac{1}{6x^2y^3}=\dfrac{7x^2}{42x^4y^3}\)

\(\dfrac{-5}{21xy^2}=\dfrac{-10x^3y}{42x^4y^3}\)

\(\dfrac{3}{14x^4y}=\dfrac{3\cdot3y}{42x^4y^3}=\dfrac{9y}{42x^4y^3}\)

b: \(\dfrac{2}{x^3-y^3}=\dfrac{2}{\left(x-y\right)\left(x^2+xy+y^2\right)}=\dfrac{2\left(x+y\right)}{\left(x-y\right)\left(x+y\right)\left(x^2+xy+y^2\right)}\)

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

28 tháng 6 2017

Quy đồng mẫu thức nhiều phân thức

Quy đồng mẫu thức nhiều phân thức

20 tháng 11 2018

\(\frac{-3}{x^2+6x+8}=\frac{-3}{x\left(x+2\right)+4\left(x+2\right)}=\frac{-3}{\left(x+2\right)\left(x+4\right)}=\frac{-3x+12}{\left(x+2\right)\left(x+4\right)\left(x-4\right)}\)

\(\frac{5}{x^2-16}=\frac{5}{\left(x-4\right)\left(x+4\right)}=\frac{5x+10}{\left(x+2\right)\left(x-4\right)\left(x+4\right)}\)

\(\frac{1}{x^2-2x-8}=\frac{1}{x\left(x-4\right)+2\left(x-4\right)}=\frac{1}{\left(x-4\right)\left(x+2\right)}=\frac{x+4}{\left(x+2\right)\left(x+4\right)\left(x-4\right)}\)

\(\dfrac{-5}{6x^5y^3}=\dfrac{-5\cdot2\cdot y^3}{12x^5y^6}=\dfrac{-10y^3}{12x^5y^6}\)

\(\dfrac{3}{4x^2y^6}=\dfrac{3\cdot3x^3}{12x^5y^6}=\dfrac{9x^3}{12x^5y^6}\)

\(\dfrac{7}{3x^4y^5}=\dfrac{7\cdot4\cdot x\cdot y}{12x^5y^6}=\dfrac{28xy}{12x^5y^6}\)

a) MTC: \(12x^3y^3\)

\(\dfrac{3}{4x^3y^2}=\dfrac{3\cdot3y}{4x^3y^2\cdot3y}=\dfrac{9y}{12x^3y^3}\)

\(\dfrac{2}{3xy^3}=\dfrac{2\cdot4x^2}{3xy^3\cdot4x^2}=\dfrac{8x^2}{12x^3y^3}\)

b) MTC: \(x\left(x-3\right)^2\)

\(\dfrac{5}{x^2-6x+9}=\dfrac{5}{\left(x-3\right)^2}=\dfrac{5x}{x\left(x-3\right)^2}\)

\(\dfrac{3}{x^2-3x}=\dfrac{3}{x\left(x-3\right)}=\dfrac{3\left(x-3\right)}{x\left(x-3\right)^2}=\dfrac{3x-9}{x\left(x-3\right)^2}\)