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2 tháng 10 2016

\(2x^2-3ax-9a^2\)

\(=2x^2-6ax+3ax-9a^2\)

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

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

\(2x^2-17xy-9y^2\)

\(=2x^2+xy-18xy-9y^2\)

\(=2x\left(2x+y\right)-9y\left(2x+y\right)\)

\(=\left(2x+y\right)\left(2x-9y\right)\)

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. \(4x^2-17xy+13y^2=4x^2-4xy-13xy+13y^2=4x\left(x-y\right)-13y\left(x-y\right)=\left(x-y\right)\left(4x-13y\right)\)

2. \(2x\left(x-5\right)-x\left(3+2x\right)=26\Leftrightarrow2x^2-10x-3x-2x^2=26\Leftrightarrow-13x=26\Leftrightarrow x=-2\)

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

\(\Leftrightarrow\left(2a-3b\right)^2-2\left(2a-3b\right)\left(2b-3a\right)+\left(2b-3a\right)^2=\left(2a-3b-2b+3a\right)^2=\left(5a-5b\right)^2\)

\(=25\left(a-b\right)^2=25\cdot100=2500\)

7 tháng 12 2018

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

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

\(=2x^2-6x+4\)

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

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

\(=2.\left[x.\left(x-1\right)-2.\left(x-1\right)\right]\)

\(=2.\left(x-1\right)\left(x-2\right)\)

7 tháng 12 2018

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

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

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

\(b,x^2-6xy-16+9y^2\)

\(=\left(x^2-6xy+9y^2\right)-16\)

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

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

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

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

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

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

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

4 tháng 8 2017

a) 4x2 +4x+3=4x2 +4x+4-1=(2x-2)2 - 1=(2x-2-1)(2x-2+1)=(2x-3)(2x-1)

4 tháng 8 2017

a) \(4x^2+4x+3\)

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

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

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

\(\left(2x+3\right)\left(2x+1\right)\)

c) \(x^2-a^2+2ab-b^2\)

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

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

9 tháng 10 2018

1. \(4x^2-2x-3y-9y^2\)

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

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

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

2. \(x^2-25=6x-9\)

\(\Rightarrow x^2-6x+9=25\)

\(\Rightarrow\left(x-3\right)^2=25\)

\(\Rightarrow\orbr{\begin{cases}x-3=5\\x-3=-5\end{cases}}\Rightarrow\orbr{\begin{cases}x=8\\x=-2\end{cases}}\)

25 tháng 7 2018

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

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

c) \(4x^2-9y^2=\left(4x-9y\right)\left(4x+9y\right)\)

d) \(x^3-27y^3=\left(x-3y\right)\left(x^2+3xy+9y^2\right)\)

25 tháng 7 2018

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

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

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

d)\(x^3-27y^3=\left(x-3y\right)\left(x^2+3xy+9y^2\right)\)

20 tháng 8 2020

Bài làm:

Ta có: \(a^2x^2+b^2y^2-a^2y^2-b^2x^2\)

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

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

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

20 tháng 8 2020

\(a^2x^2+b^2y^2-a^2y^2-b^2x^2\)

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

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

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