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16 tháng 10 2018

Ta có:

\(x^2y^2\left(y-x\right)+y^2z^2\left(z-y\right)-z^2x^2\left(z-x\right)\)

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

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

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

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

\(=\left(y-x\right)\left(x-z\right)\left(y-z\right)\left(xy+yz+zx\right)\)

5 tháng 10 2021

\(3,=\left(x-y\right)^3+\left(y-x+x-z\right)^3+\left(z-x\right)^3\\ =\left(x-y\right)^3+\left(y-x\right)^3+3\left(y-x\right)\left(x-z\right)\left(y-x+x-z\right)+\left(x-z\right)^3+\left(z-x\right)^3\\ =\left(x-y\right)^3-\left(x-y\right)^3+3\left(y-x\right)\left(x-z\right)\left(y-z\right)-\left(z-x\right)^3+\left(z-x\right)^3\\ =3\left(y-x\right)\left(x-z\right)\left(y-z\right)\)

\(4,=\left(x^4+3x^3-x^2\right)+\left(3x^3+9x^2-3x\right)-\left(x^2+3x-1\right)\\ =x^2\left(x^2+3x-1\right)+3x\left(x^2+3x-1\right)-\left(x^2+3x-1\right)\\ =\left(x^2+3x-1\right)\left(x^2+3x-1\right)\\ =\left(x^2+3x-1\right)^2\)

14 tháng 1 2022

yz(y+z)+zx(z+x)+xy(x+y)+2xyz

=yz(y+z+x-x)+zx(z+x+x-x)+xy(x+y)+2xyz

=(x-z)(yz+zx)+(x+y)(yz+xy)+2x2z+2xyz

=y(x-z)(x+y)+y(x+z)(x+y)+2xz(x+y)

=(x+y)[y(x-z)+y(x+z)+2xz]

=(x+y)(yx-yz+yx+yz+2xz)

=(x+y)2x(y+z)

14 tháng 1 2022

Mình sợ sai ấy, bạn kiểm tra lại đi

7 tháng 4 2017

\(x^2\left(y-z\right)+y^2\left(z-x\right)+z^2\left(x-y\right)\)

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

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

\(=\left[x^2\left(y-z\right)-y^2\left(y-z\right)\right]+\left[y^2\left(y-x\right)-z^2\left(y-x\right)\right]\)

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

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

\(=\left(x-y\right)\left(y-z\right)\left[\left(x+y\right)-\left(y+z\right)\right]\)

\(=\left(x-y\right)\left(y-z\right)\left(x-z\right)\)

7 tháng 4 2017

Thanks you!!!

16 tháng 11 2015

Ta có: M = xy(x+y) + yz(y+z) + xz (x+z) + 2xyz 

= xy(x + y) + yz(y + z) + xyz + xz(x + z) + xyz 

= xy(x + y) + yz(y + z + x) + xz(x + z + y) 

= xy(x + y) + z(x + y + z)(x + y) 

= (x + y)(xy + zx + zy + z2

= (x + y)[x(y + z) + z(y + z)] 

M = (x + y)(y + z)(z + x) (đpcm)

15 tháng 12 2023

\(\left(x+y+z\right)^3-x-y-z\\ =\left(x+y+z\right)^3-\left(x+y+z\right)\\ =\left(x+y+z\right)\left(\left(x+y+z\right)^2-1\right)\\ =\left(x+y+z\right)\left(x+y+z-1\right)\left(x+y+z+1\right)\)