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29 tháng 9 2019

a) =(x-y)5+(x-y)3=(x-y)3[(x-y)2+1]

b) =33(y-2x)3:-9(y-2x)=-3(y-2x)2

c) =(x-y)2 [3(x-y)3-2(x-y)2+3]:5(x-y)2=[3(x-y)3-2(x-y)2+3]/5

12 tháng 8 2020

a, \(3x\left(x^3-2x\right)=3x^4-6x^2\)

b, \(\frac{4y^3}{7x^2}.\frac{14x^3}{y}=\frac{56x^3y^3}{7x^2y}\)tự chia nhé

c, \(\frac{x^2-9}{2x+6}:\frac{3-x}{2}=\frac{x^2-9}{2x+6}.\frac{2}{3-x}=\frac{2x^2-18}{6x-2x^2+18-6x}=\frac{2x^2-18}{-2x^2+18}=1\)

a: \(=\left(\dfrac{9}{x\left(x-3\right)\left(x+3\right)}+\dfrac{1}{x+3}\right):\left(\dfrac{x-3}{x\left(x+3\right)}-\dfrac{x}{3\left(x+3\right)}\right)\)

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

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

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

b: \(=\dfrac{x+1}{x+2}:\left(\dfrac{\left(x+2\right)\left(x+1\right)}{\left(x+3\right)^2}\right)\)

\(=\dfrac{x+1}{x+2}\cdot\dfrac{\left(x+3\right)^2}{\left(x+2\right)\left(x+1\right)}=\dfrac{\left(x+3\right)^2}{\left(x+2\right)^2}\)

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

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

\(=\dfrac{\left(x+y\right)}{x-y}\)

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

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

\(=\dfrac{x}{x+3}+\dfrac{3}{x-3}-\dfrac{6x}{\left(x-3\right)\left(x+3\right)}\)

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

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

c: \(=\dfrac{x+9}{\left(x-3\right)\left(x+3\right)}-\dfrac{3}{x\left(x+3\right)}\)

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

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

d: \(=\dfrac{x^2-1-x^2+4}{x+1}=\dfrac{3}{x+1}\)

11 tháng 7 2019

rút gọn đây là đề bài

13 tháng 7 2019

Duy Nguyễn, Duy Nguyễn, Duy Nguyễn, Duy Nguyễn, Duy nguyễn, Duy Nguyễn, Duy Nguyễn, Duy Nguyễn, Duy Nguyễn

giúp bn ấy vs

21 tháng 10 2016

A = \(\frac{3}{5}\)a - \(\frac{4}{5}\) b2

B = 3x - 5y + 4x

21 tháng 10 2016

TỚ nhầm. B ko thực hiện đc nhé

29 tháng 10 2017

1,Thực hiện phép tính :

a, (x + 2)9 : (x + 2)6

=(x+2)9-6

=(x+2)3

b, (x - y) 4 : (x - 2)3

=(x-y)4-3

=x-y

c, ( x2+ 2x + 4)5 : (x2 + 2x + 4)

=(x2+2x+4)5-1

=(x2+2x+4)4

d, 2(x2 + 1)3 : 1/3(x2 + 1)

=(2÷1/3).[(x2+1)3÷(x2+1)]

=6(x2+1)2

e, 5 (x - y)5 : 5/6 (x - y)2

=(5÷5/6).[(x-y)5÷(x-y)2]

=6(x-y))3