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Đề bài là gì sao không ghi rõ?? 

a) Ta có: \(4\left(2-x\right)^2+xy-2y\)

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

\(=\left(x-2\right)\left[4\left(x-2\right)+y\right]\)

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

b) Ta có: \(3a^2x-3a^2y+abx-aby\)

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

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

\(=a\left(x-y\right)\left(3a+b\right)\)

c) Ta có: \(x\left(x-y\right)^3-y\left(y-x\right)^2-y^2\left(x-y\right)\)

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

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

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

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

d) Ta có: \(2ax^3+6ax^2+6ax+18a\)

\(=2ax^2\left(x+3\right)+6a\left(x+3\right)\)

\(=\left(x+3\right)\left(2ax^3+6a\right)\)

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

e) Ta có: \(x^2y-xy^2-3x+3y\)

\(=xy\left(x-y\right)-3\left(x-y\right)\)

\(=\left(x-y\right)\left(xy-3\right)\)

21 tháng 7 2017

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

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

b, \(xy+xz+3y+3z=x\left(y+z\right)+3\left(y+z\right)=\left(x+3\right)\left(y+z\right)\)

c, \(xy-xz+y-z=x\left(y-z\right)+\left(y-z\right)=\left(x+1\right)\left(y-z\right)\)

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

\(=x\left(x-y\right)-8\left(x-y\right)=\left(x-8\right)\left(x-y\right)\)

e, \(x^2+2xy+y^2-xz-yz=\left(x^2+2xy+y^2\right)-\left(xz+yz\right)\)

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

f, \(25-4x^2-4xy-y^2=25-\left(4x^2+4xy+y^2\right)\)

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

21 tháng 7 2017

1,

a, (2x + 1- x + 3)2 = (x+4)2

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

c, \(x\left(y-z\right)+\left(y-z\right)=\left(y-z\right)\left(x+1\right)\)

d,\(x\left(x-y\right)+8\left(y-x\right)\)=\(\left(x-y\right)\left(x-8\right)\)

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

f,\(25-\left(4x^2+4xy+y^2\right)=5^2-\left(2x+y\right)^2\)

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

Chúc các bn hc tốtbanh

13 tháng 5 2020

B1 : a, M = x3-3xy(x-y)-y3-x2+2xy-y2

= ( x3-y3)-3xy(x-y) -(x2-2xy+y2)

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

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

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

= (x-y)[(x-y)2-(x-y)]

= (x-y)(x-y)(x-y-1)

= (x-y)2(x-y-1)

= 72(7-1) = 49 . 6= 294

N = x2(x+1)-y2(y-1)+xy-3xy(x-y+1)-95

= x3+x2-(y3-y2)+xy-(3x2y-3xy2+3xy)-95

= x3+x2-y3+y2+xy-3x2y+3xy2-3xy-95

= (x3-y3)+(x2-2xy+y2)-(3x2y+y2)-(3x2y-3xy2)-95

=(x-y)(x2+xy+y2)+(x-y)2-3xy(x-y)-95

= (x-y)(x2+xy+y2+x-y-3xy)-95

= (x-y)[(x2-2xy+y2)+(x-y)]-95

= (x-y)[(x-y)2+(x-y)]-95

=(x-y)(x-y)(x-y+1)-95

= (x-y)2(x-y+1)-95

= 72(7+1)-95=297