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DD
9 tháng 10 2021

\(x^4y^4+16+\left(xy+2\right)^4=t^4+16+\left(t+2\right)^4\)(\(t=xy\))

\(=t^4+16+\left(t^2+4t+4\right)^2=t^4+16+\left(t^2+2t+4\right)^2+4t\left(t^2+2t+4\right)+4t^2\)

\(=\left(t^2+2t+4\right)^2+t^4+4t^3+12t^2+16t+16\)

\(=2\left(t^2+2t+4\right)^2\)

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

11 tháng 12 2017

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

x2 + 4xy - 16 + 4y2 = (x2 + 4xy + 4y2) - 16 = (x + 2y)2 - 16 = (x + 2y + 4)(x + 2y - 4)

11 tháng 12 2017

cảm ơn nha

18 tháng 10 2021

1.A

2.C

3.B

4.C

15 tháng 12 2021

a

c

b

c

23 tháng 5 2022

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

12 tháng 9 2015

a)x^2-4xy+4y^2-4

=(x2-4xy+4y2)-4

=(x-2y)2-4

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

 

b)16-x^2+2xy-y^2

=16-(x2-2xy+y2)

=16-(x-y)2

=[4-(x-y)][4+(x-y)]

=(4-x+y)(4+x-y)

 

13 tháng 10 2016

\(4x^2+8xy-3x-6y=4x\left(x+2y\right)-3\left(x+2y\right)=\left(4x-3\right)\left(x+2y\right)\)

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

\(x^3-5x^2-14x=x\left(x^2-5x-14\right)=x\left(x^2-7x+2x-14\right)=x\left[x\left(x-7\right)+2\left(x-7\right)\right]=x\left(x-7\right)\left(x+2\right)\)

\(x^4+4y^4=\left(x^2\right)^2+2\times x^2\times2y^2+\left(2y^2\right)^2-4x^2y^2=\left(x^2+2y^2\right)^2-\left(2xy\right)^2=\left(x^2-2xy+2y^2\right)\left(x^2+2xy+2y^2\right)\)

13 tháng 10 2016

thank bạn nhiều nha

7 tháng 8 2018

y^4+64

=(y^2)^2+16y^2+64-16y^2

=(y^2+8-4x)(x^2+8+4x)

x^2+4

=x^2+2x^2+4-2x^2

=(x+2)^2-2x^2

=(x^2+2-2x)(x^2+2+2x)

x^4+16

=(x^2)^2+4x^2+16-4x^2

=(x+4)^2-4x^2

=(x^2+4-4x)(x^2+4+4x)

x^4y^4+4

=x^4y^4+4x^4+2^2-4x^4

=(x^4y^4+2)^2-(2x^2)^2

=(x^4y^4+2+2x^2)(x^4y^4+2-2x^2)

4x^4y^4+1

=4x^4y^4+x^4+1-x^4

=(2x^4y^4+1)^2-(x^2)^2

=(2x^4y^4+1-x^2)(2x^4y^4+1+x^2)

Mình ko bt câu D đúng hay sai nữa. Mà lỡ sai bạn đừng giận mình nha!

1: =(x+y-3x)(x+y+3x)

=(-2x+y)(4x+y)

2: =(3x-1-4)(3x-1+4)

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

=3(x+1)(3x-5)

3: =(2x)^2-(x^2+1)^2

=-[(x^2+1)^2-(2x)^2]

=-(x^2+1-2x)(x^2+1+2x)

=-(x-1)^2(x+1)^2

4: =(2x+1+x-1)(2x+1-x+1)

=3x(x+2)

5: =[(x+1)^2-(x-1)^2][(x+1)^2+(x-1)^2]

=(2x^2+2)*4x

=8x(x^2+1)

6: =(5x-5y)^2-(4x+4y)^2

=(5x-5y-4x-4y)(5x-5y+4x+4y)

=(x-9y)(9x-y)

7: =(x^2+xy+y^2+xy)(x^2+xy-y^2-xy)

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

=(x+y)^3*(x-y)

8: =(x^2+4y^2-20-4xy+16)(x^2+4y^2-20+4xy-16)

=[(x-2y)^2-4][(x+2y)^2-36]

=(x-2y-2)(x-2y+2)(x+2y-6)(x+2y+6)

14 tháng 10 2020

16) 2x + 2y - x2 - xy = ( 2x + 2y ) - ( x2 + xy ) = 2( x + y ) - x( x + y ) = ( x + y )( 2 - x )

17) x2 - 2x - 4y2 - 4y = ( x2 - 4y2 ) - ( 2x + 4y ) = ( x - 2y )( x + 2y ) - 2( x + 2y ) = ( x + 2y )( x - 2y - 2 )

18) x2y - x3 - 9y + 9x = ( x2y - x3 ) - ( 9y - 9x ) = x2( y - x ) - 9( y - x ) = ( y - x )( x2 - 9 ) = ( y - x )( x - 3 )( x + 3 )

19) x2( x - 1 ) + 16( 1 - x ) = x2( x - 1 ) - 16( x - 1 ) = ( x - 1 )( x2 - 16 ) = ( x - 1 )( x - 4 )( x + 4 )

20) 2x2 + 3x - 2xy - 3y = ( 2x2 - 2xy ) + ( 3x - 3y ) = 2x( x - y ) + 3( x - y ) = ( x - y )( 2x + 3 )

14 tháng 10 2020

20, \(2x^2+3x-2xy-3y=2x\left(x-y\right)+3\left(x-y\right)=\left(2x+3\right)\left(x-y\right)\)

16, \(2x+2y-x^2-xy=2\left(x+y\right)-x\left(x+y\right)=\left(2-x\right)\left(x+y\right)\)

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

18, \(x^2y-x^3-9y+9x=-x\left(x^2-9\right)+y\left(x^2-9\right)=\left(-x-y\right)\left(x^2-9\right)=\left(y-x\right)\left(x-3\right)\left(x+3\right)\)

19, \(x^2\left(x-1\right)+16\left(1-x\right)=x^2\left(x-1\right)-16\left(x-1\right)=\left(x^2-16\right)\left(x-1\right)=\left(x-4\right)\left(x+4\right)\left(x-1\right)\)

30 tháng 7 2021

a) `x^4+2x^3-4x-4`

`=(x^4-4)+(2x^3-4x)`

`=(x^2-2)(x^2+2)+2x(x^2-2)`

`=(x^2-2)(x^2+2+2x)`

b) `x^3-4x^2+12x-27`

`=(x^3-27)-(4x^2-12x)`

`=(x-3)(x^2+3x+9)-4x(x-3)`

`=(x-3)(x^2+3x+9-4x)`

`=(x-3)(x^2-x+9)`

c) `xy-4y-5x+20`

`=y(x-4)-5(x-4)`

`=(y-5)(x-4)`

a) Ta có: \(x^4+2x^3-4x-4\)

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

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

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

b) Ta có: \(x^3-4x^2+12x-27\)

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

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

c) Ta có: \(xy-4y-5x+20\)

\(=y\left(x-4\right)-5\left(x-4\right)\)

\(=\left(x-4\right)\left(y-5\right)\)

21 tháng 9 2020

a) x2 - y2 - 4x + 4y

= (x2 - 4x + 4) - (y2 - 4y + 4)

= (x - 2)2 - (y - 2)2

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

= (x - y)(x + y - 4)

b) (xy + 4)2 - 4(x + y)2

= (xy + 4)2 - [2(x + y)]2

= (xy + 4)2 - (2x + 2y)2

= (xy + 4 - 2x - 2y)(xy + 4 + 2x + 2y)

c) 25 - x2 + 2xy - y2

= 25 - (x2 - 2xy + y2)

= 52 - (x - y)2

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

21 tháng 9 2020

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

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

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

c) \(25-x^2+2xy-y^2=25-\left(x^2-2xy+y^2\right)=5^2-\left(x-y\right)^2=\left(5+x-y\right)\left(5-x+y\right)\)