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8 tháng 3 2017

a)\(x^2-y^2-x+3y-2=\left(x^2+xy-2x\right)-\left(xy+y^2-2y\right)+\left(x+y-2\right)\)

\(=x\left(x+y-2\right)-y\left(x+y-2\right)+\left(x+y-2\right)\)

\(=\left(x+y-2\right)\left(x-y+1\right)\)

b)\(x^3+y^3+6xy+x+y-10\)

\(=\left(x^3+xy^2-x^2y+2x^2+2xy+5x\right)+\left(y^3+x^2y+xy^2+2y^2+2xy+5y\right)-\left(2x^2+2y^2-2xy+4x+4y+10\right)\)

\(=x\left(x^2+y^2-xy+2x+2y+5\right)+y\left(y^2+x^2-xy+2y+2x+5\right)-2\left(x^2+y^2-xy+2x+2y+5\right)\)\(=\left(x+y-2\right)\left(x^2+y^2-xy+2x+2y+5\right)\)

`@` `\text {Ans}`

`\downarrow`

`a,`

`3x + 6xy + 3y - 3z`

`= 3(x + 2y + y - z)`

`b,`

`x+ xy - xz - xyz`

`= x(1 + y)*(1-z)`

a: 3x^2+6xy+3y^2-3z^2

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

=3[(x+y)^2-z^2]

=3(x+y+z)(x+y-z)

b: x+xy-xz-xyz

=x(y+1)-xz(y+1)

=(y+1)*x*(1-z)

13 tháng 10 2021

\(a,=\left(x-2\right)\left(15x-7y\right)\\ b,=x\left(x-11\right)\left(2x-1\right)\\ c,=2x\left(x-3\right)\left(2+3y\right)\\ d,=\left(x-y\right)\left(x-7y\right)\\ e,=\left(x-3\right)\left(4x-12-2x\right)\\ =\left(x-3\right)\left(2x-12\right)=2\left(x-6\right)\left(x-3\right)\)

20 tháng 10 2021

2)3x2-6xy+3y2=3(x2-2xy+y2)=3(x-y)2

3)3(x-y)-5y(y-x)=3(x-y)+5y(x-y)=(x-y)(3+5y)

5)(x+y)3-(x-y)3=[(x+y)-(x-y)][(x+y)2+(x+y)(x-y)+(x-y)2]=(x+y-x+y)(x2+2xy+y2+x2-y2+x2-2xy+y2)=2y(3x2+y2)

6)3x2-5x+2=3x2-2x-3x+2=(3x2-3x)-(2x-2)=3x(x-1)-2(x-1)=(x-1)(3x-2)

Bài 1: 

a: Ta có: \(\left(6x+3\right)-\left(2x-5\right)\left(2x+1\right)\)

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

\(=\left(2x+1\right)\left(8-2x\right)\)

\(=2\left(4-x\right)\left(2x+1\right)\)

b) Ta có: \(\left(3x-2\right)\left(4x-3\right)-\left(2-3x\right)\left(x-1\right)-2\left(3x-2\right)\left(x+1\right)\)

\(=\left(3x-2\right)\left(4x-3\right)+\left(3x-2\right)\left(x-1\right)-\left(3x-2\right)\left(2x+2\right)\)

\(=\left(3x-2\right)\left(4x-3+x-1-2x-2\right)\)

\(=\left(3x-2\right)\left(3x-6\right)\)

\(=3\left(3x-2\right)\left(x-2\right)\)

Bài 2: 

a: Ta có: \(\left(a-b\right)\left(a+2b\right)-\left(b-a\right)\left(2a-b\right)-\left(a-b\right)\left(a+3b\right)\)

\(=\left(a-b\right)\left(a+2b\right)+\left(a-b\right)\left(2a-b\right)-\left(a-b\right)\left(a+3b\right)\)

\(=\left(a-b\right)\left(a+2b+2a-b-a-3b\right)\)

\(=\left(a-b\right)\left(2a-4b\right)\)

\(=2\left(a-b\right)\left(a-2b\right)\)

f: Ta có: \(x^2-6xy+9y^2+4x-12y\)

\(=\left(x-3y\right)^2+4\left(x-3y\right)\)

\(=\left(x-3y\right)\left(x-3y+4\right)\)

12 tháng 10 2021

Bài 2: 

a: \(3x^2-3xy=3x\left(x-y\right)\)

b: \(x^2-4y^2=\left(x-2y\right)\left(x+2y\right)\)

c: \(3x-3y+xy-y^2=\left(x-y\right)\left(3+y\right)\)

d: \(x^2-y^2+2y-1=\left(x-y+1\right)\left(x+y-1\right)\)

18 tháng 10 2021

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1 tháng 10 2021

a) \(x^3y^3+125=\left(xy\right)^3+5^3=\left(xy+5\right)\left(x^2y^2-5xy+25\right)\)

b) \(8x^3+y^3-6xy\left(2x+y\right)=\left(8x^3+y^3\right)-6xy\left(2x+y\right)=[\left(2x\right)^3+y^3]-6xy\left(2x+y\right)\)

\(=\left(2x+y\right)\left(4x^2-2xy+y^2\right)-6xy\left(2x+y\right)=\left(2x+y\right)\left(4x^2-2xy+y^2-6xy\right)\)

\(=\left(2x+y\right)\left(4x^2-8xy+y^2\right)\)

c) \(\left(3x+2\right)^2-2\left(x-1\right)\left(3x+2\right)+\left(x-1\right)^2\)

\(=[\left(3x+2\right)-\left(x-1\right)]^2=\left(3x+2-x+1\right)^2=\left(2x+3\right)^2=\left(2x+3\right)\left(2x+3\right)\)