\(x^2-2x-4y^2-4y\)

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15 tháng 7 2019

Cái này thì bn sử dụng hằng đẳng thức là đc bạn nhé!

15 tháng 7 2019

\(x^2+4xy+4y^2-2x-4y+1\)

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

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

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

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

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

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

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

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

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

8 tháng 8 2018

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

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

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

1 tháng 1 2019

\(x^2-2x-4y^2-4y\)

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

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

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

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

4 tháng 8 2017

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

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

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

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

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

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

4 tháng 8 2017

a.x2-2x-4y2-4y=(x2-4y2)-(2x+4y)=(x-2y)(x+2y)-2(x+2y)=(x+2y)(x-2y-2)

b.x4+2x3-4x-4=(x4-4)+(2x3-4x)=(x2-2)(x2+2)+2x(x2-2)=(x2-2)(x2+2x+2)

c.x2(1-x2)-4-4x2= -x4-3x2-4=x2-(x4+4x2+4)=x2-(x2+2)2=(x-x2-2)(x+x2+2)

26 tháng 7 2018

\(\left(ab+1\right)^2-\left(a+b\right)^2=\left(ab+1+a+b\right)\left(ab+1-a-b\right).\)

\(=\left(a+1\right)\left(b+1\right)\left(a-1\right)\left(b-1\right)\)

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

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

26 tháng 8 2020

Bài làm:

1) Ta có: \(2x^2+5xy+2y^2\)

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

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

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

2) Ta có: \(2x^2+2xy-4y^2\)

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

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

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

26 tháng 8 2020

\(1)2x^2+5xy+2y^2=2x^2+4xy+xy+2y^2=\left(2x^2+4xy\right)+\left(xy+2y^2\right)=2x\left(x+2y\right)+y\left(x+2y\right)=\left(2x+y\right)\left(x+2y\right)\)\(2)2x^2+2xy-4y^2=2x^2+4xy-2xy-4y^2=\left(2x^2-2xy\right)+\left(4xy-4y^2\right)=2x\left(x-y\right)+4y\left(x-y\right)=\left(2x+4y\right)\left(x-y\right)\)

1 tháng 10 2018

d,

\(a^2+2ab+b^2-ac-bc=\left(a+b\right)^2-c\left(a+b\right)\)

\(=\left(a+b\right)\left(a+b-c\right)\)

Vậy..

1 tháng 10 2018

e

\(x^2-2x-4y^2-4y\)

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

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

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

3 tháng 7 2018

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

2, \(=2\left(x^2-y^2\right)+8\left(x+1\right)=2\left(x+1\right)\left(x-1\right)+8\left(x+1\right)=2\left(x+1\right)\left(x-1+4\right)=2\left(x+1\right)\left(x+3\right)\)

3, \(=\left(x^2+6x+9\right)-\left(2y\right)^2=\left(x+3\right)^2-\left(2y\right)^2=\left(x+3-2y\right)\left(x+3+2y\right)\)

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

30 tháng 9 2018

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

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

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

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

hk tốt

^^