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30 tháng 8 2020

a) 16x2 - 9 

= ( 4x )2 - 32

= ( 4x - 3 )( 4x + 3 )

b) 9a2 - 25b4

= ( 3a )2 - ( 5b2 )2

= ( 3a - 5b2 )( 3a + 5b2 )

c) 81 - y4

= 92 - ( y2 )2

= ( 9 - y2 )( 9 + y2 )

= ( 32 - y2 )( 9 + y2 )

= ( 3 - y )( 3 + y )( 9 + y2 )

d) ( 2x + y )2 - 1

= ( 2x + y )2 - 12

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

e) ( x + y + z )2 - ( x - y - z )2

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

= [ x + y + z - x + y + z ][ x + y + z + x - y - z ]

= [ 2y + 2z ].2x

= 2[ y + z ].2x

= 4x[ y + z ]

29 tháng 9 2022

a) x2+2x+1= (x+1)2

b) 9x2+6xy+y2= (3x+y)2

 

22 tháng 8 2020

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

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

b, \(\left(2x+3\right)^2+\left(2x-3\right)^2-2\left(4x^2-9\right)=4x^2+12x+9+4x^2-12x+9-8x^2+18\)

\(=36\)

1 tháng 8 2017

\(1.\)

\(x^3z+x^2yz-x^2z^2-xyz^2\)

\(=x^3z-x^2z^2+x^2yz-xyz^2\)

\(=x^2z\left(x-z\right)-xyz\left(x-z\right)\)

\(=\left(x^2z-xyz\right)\left(x-z\right)\)

\(=xz\left(x-y\right)\left(x-z\right)\)

\(2.\)

\(x^2-\left(a+b\right)xy+aby^2\)

\(=x^2-axy-bxy+aby^2\)

\(=x^2-bxy-axy+aby^2\)

\(=x\left(x-by\right)-ay\left(x-by\right)\)

\(=\left(x-ay\right)\left(x-by\right)\)

\(3.\)

\(ab\left(x^2+y^2\right)+xy\left(x^2+y^2\right)\)

\(=abx^2+aby^2+a^2xy+b^2xy\)

\(=abx^2+b^2xy+a^2xy+aby^2\)

\(=bx\left(ax+by\right)+ay\left(ax+by\right)\)

\(=\left(ax+by\right)\left(bx+ay\right)\)

\(4.\)

\(\left(xy+ab\right)^2+\left(ay-bx\right)^2\)

\(=x^2y^2+2abxy+a^2b^2+a^2y^2-2aybx+b^2x^2\)

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

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

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

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

\(5.\)

\(a^2\left(b-c\right)+b^2\left(c-a\right)+c^2\left(a-b\right)\)

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

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

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

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

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

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

\(=\left(a-b\right)\left[b\left(a-c\right)-c\left(a-c\right)\right]\)

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

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

\(6.\)

\(16x^2-40xy+2y^2\)

\(=\left(4x\right)^2-2\cdot4\cdot5xy+\left(5y\right)^2\)

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

\(7.\)

\(25x^4-10x^2y+y^2\)

\(=\left(5x^2\right)^2-2\cdot5x^2y+y^2\)

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

\(8.\)

\(-16x^4y^6-24x^5y^5-9x^6y^4\)

\(=-\left(4^2x^4y^6+2\cdot4\cdot3x^5y^5+3^2x^6y^4\right)\)

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

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

\(9.\)

\(16x^2-4y^2-8x+1\)

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

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

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

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

\(10.\)

\(49x^2-25+42xy+9y^2\)

\(=\left(7x\right)^2-5^2+2\cdot7\cdot3xy+\left(3y\right)^2\)

\(=\left(7x\right)^2+2\cdot7\cdot3xy+\left(3y\right)^2-5^2\)

\(=\left(7x+3y\right)^2-5^2\)

\(=\left(7x+5y+5\right)\left(7x+3y-5\right)\)

29 tháng 7 2016

Bài 1: 4a2-4ab+b2-9a2b2

=(2a)2-2.2a.b+b2-(3ab)2

=(2a-b)2-(3ab)2

=(2a-b-3ab)(2a-b+3ab)

29 tháng 7 2016

a/ (4a2-4ab+b2)-9a2b2

= (2a-b)2-(3ab)2

= (2a-b-3ab) (2a-b+3ab)