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1 tháng 11 2016

Đây, bản full đây thím, tớ thực sự đã kiên nhẫn lắm đấy ...

a)\(4\left(x^2-y^2\right)-8\left(x-ay\right)-4\left(a^2-1\right)=4\left(x^2-y^2-2x+2ay-a^2+1\right)\)

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

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

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

b)\(\left(x+y\right)^3-1-3xy\left(x+y-1\right)\)

\(=\left(x+y-1\right)\left[\left(x+y\right)^2+x+y+1\right]-3xy\left(x+y-1\right)\)

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

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

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

c)\(x^3-1+5x^2-5+3x-3=\left(x-1\right)\left(x^2+x+1\right)+5\left(x^2-1\right)+3\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2+x+1\right)+5\left(x-1\right)\left(x+1\right)+3\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2+x+1\right)+\left(x-1\right)\left(5x+5\right)+3\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2+x+1+5x+5+3\right)\)

\(=\left(x-1\right)\left(x^2+6x+9\right)\)

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

d)\(a^5+a^4+a^3+a^2+a+1=a^4\left(a+1\right)+a^2\left(a+1\right)+\left(a+1\right)\)

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

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

\(=\left(a+1\right)\left[\left(a^2+1\right)^2-a^2\right]\)

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

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

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

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

f)\(5x^3-3x^2y-45xy^2+27y^3=5x\left(x^2-9y^2\right)-3y\left(x^2-9y^2\right)\)

\(=\left(x^2-9y^2\right)\left(5x-3y\right)\)

\(=\left(x-3y\right)\left(x+3y\right)\left(5x-3y\right)\)

g)\(3x^2\left(a-b+c\right)+36xy\left(a-b+c\right)+108y^2\left(a-b+c\right)\)

\(=\left(a-b+c\right)\left(3x^2+36xy+108y^2\right)\)

\(=3\left(a-b+c\right)\left(x^2+12xy+36y^2\right)\)

\(=3\left(a-b+c\right)\left(x+6y\right)^2\)

1 tháng 11 2016

a/ \(4\left(x^2-y^2\right)-8\left(x-ay\right)-4\left(a^2-1\right)\)

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

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

b/ \(\left(x+y\right)^3-1-3xy\left(x+y-1\right)=\left(x+y-1\right)\left(x^2+y^2+2xy+x+y+1\right)-3xy\left(x+y-1\right)\)

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

Giải giúp bạn 2 bài tiêu biểu thôi nha

5 tháng 1 2019

\(\frac{2}{5}x\left(y-1\right)-\frac{2}{5}y\left(y-1\right)\)

\(=\left(y-1\right)\left[\left(\frac{2}{5}x-\frac{2}{5}y\right)\right]\)

\(=\left(y-1\right)\frac{2}{5}\left(x-y\right)\)

5 tháng 1 2019

\(\frac{1}{25}x^2-64y^2\)

\(=\left(\frac{1}{5}x\right)^2-8^2\)

\(=\left(\frac{1}{5}x+8\right)\left(\frac{1}{5}x-8\right)\)

27 tháng 10 2021

helpppppp

10 tháng 8 2016

a) 4(x2-y2)-8(x-ay)-4(a2-1)

    => 4x2-4y2-8x+8ay-4a2+4

    => 4(x2-y2-2x+2ay-a2+1)

c) a5+a4+a3 +a2 +a+1

    => a(a4+a3+a2+a+1)+1

10 tháng 10 2018

      \(a^3-a^2x-ay+xy\)

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

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

       \(4x^2-y^2+4x+1\)

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

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

       \(x^3-x+y^3-y\)

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

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

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

10 tháng 10 2018

a)a3 - a2x - ay +xy

=(a3 - a2x) - (ay - xy)

=a2(a-x) - y(a-x)

=(a-x).(a2 - y)

29 tháng 8 2018

mk viết đáp án, ko biết biến đổi ib mk

a)  \(x^3+3x^2y-9xy^2+5y^3=\left(x+5y\right)\left(x-y\right)^2\)

b)    \(x^4+x^3+6x^2+5x+5=\left(x^2+5\right)\left(x^2+x+1\right)\)

c)   \(x^4-2x^3-12x^2+12x+36=\left(x^2-6\right)\left(x^2-2x-6\right)\)

d)   \(x^8y^8+x^4y^4+1=\left(x^2y^2-xy+1\right)\left(x^2y^2+xy+1\right)\left(x^4y^4-x^2y^2+1\right)\)

23 tháng 8 2020

a) -x2 + 2x - 1

= -( x2 - 2x + 1 )

= -( x - 1 )2

b) 12y - 36 - y2

= -( y2 - 12y + 36 )

= -( y - 6 )2

c) -x3 + 9x2 - 27x + 27

= -( x3 - 9x2 + 27x - 27 )

= -( x - 3 )3

d) x3 - 6x2 + 9x 

= x( x2 - 6x + 9 )

= x( x - 3 )2

e) a3b - ab3 

= ab( a2 - b2 )

= ab( a - b )( a + b )

f) a2 + 2a + 1 - b2

= a2 + ab + a - ab - b2 - b + a + b + 1

= a( a + b + 1 ) - b( a + b + 1 ) + 1( a + b + 1 )

= ( a - b + 1 )( a + b + 1 )

23 tháng 8 2020

a)\(-x^2+2x-1\) 

\(=-\left(x^2-2x+1\right)\)  

\(=-\left(x-1\right)^2\) 

b) \(12y-36-y^2\)    

\(=-\left(y^2-12y+36\right)\)    

\(=-\left(y^2-2\cdot1\cdot6+6^2\right)\)      

\(=-\left(y-6\right)^2\)        

c) \(-x^3+9x^2-27x+27\)      

\(=-x^3+3x^2+6x^2-18x-9x+27\)      

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

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

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

\(=\left(x-3\right)\cdot-\left(x^2-2\cdot x\cdot3+3^2\right)\) 

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

\(=\left(x-3\right)^3\)      

d) \(x^3-6x^2+9\)     

\(=x\left(x^2-6x+9\right)\)    

\(=x\left(x-3\right)^2\)    

e) \(a^3b-ab^3\)     

\(=ab\left(a^2-b^2\right)\)  

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

f) \(a^2+2a+1-b^2\)    

\(=a^2+2\cdot a\cdot1+1^2-b^2\)    

\(=\left(a+1\right)^2-b^2\)      

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