a) = (x - 2)² - y²

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

b) = (x^2 + 6x + 9) - (2y)^2

= (x + 3)² - (2y)²

= (x - 2y + 3)(x + 2y + 3)

c) = (x - 3y)² - 6²

= (x - 3y - 6)(x - 3y + 6)

a) Ta có: \(x^2y^2-x^2+6xy-9y^2\)

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

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

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

b) Ta có: \(9-x^2+2xy-y^2\)

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

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

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

a) \(2x^3+6xy-x^2z-3yz\)

= \(\left(2x^3+6xy\right)-\left(x^2z+3yz\right)\)

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

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

b)\(x^2-6xy+9y^2-49\)

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

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

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

Cứu với mn ơi , mai em có ktra ạ 

x²-6xy+9y²-36 =(x²-6xy+9y²)-36 =(x-3y)²-6² =(x-3y+6)(x-3y-6)

\(x^4+6x^3+13x^2+12x+4\)

\(=x^4+x^3+5x^3+5x^2+8x^2+8x+4x+4\)

\(=x^3\left(x+1\right)+5x^2\left(x+1\right)+8x\left(x+1\right)+4\left(x+1\right)\)

\(=\left(x+1\right)\left(x^3+5x^2+8x+4\right)\)

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

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

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

x^2+6xy+9y^2-3x-9y+2

=( x^2+6xy+9y^2)-3(x+3y)+9/4 -1/4

=(x+3y)^2-3(x+3y)+(3/2)^2- 1/4

=(x+3y+3/2)^2-(1/2)^2

=(x+3y+3/2+1/2)(x+3y+3/2-1/2)=(x+3y+2)(x+3y+1)

=[x²-6xy+(3y)²-49]

=[(x-3y)²-7²]

=(x-3y-7)*(x+3y+7)

= x^2 - 6xy + 9y^2 - 49

= x^2 - 6xy + ( 3y )^2 - 49

= (x - 3y)^2 - 7^2

= (x - 3y -7)( x-3y +7) tk cho mk nha

\(x^2-49-6xy+9y^2\)

\(=\left(x^2-6xy+9y^2\right)-7^2\)

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

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

k mk nha ^_^

Dùng hằng đẳng thức là xong

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

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

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

a) 3x² - 7x + 4

= 3x² - 3x - 4x + 4

= 3x( x - 1 ) - 4( x - 1 )

= ( x - 1 )( 3x - 4 )

b) x² - 6xy + 9y² = ( x - 3y )²

c) x² - 8x - 9

= x² - 9x + x - 9

= x( x - 9 ) + ( x - 9 )

= ( x - 9 )( x + 1 )

a) 3x² - 7x + 4

= 3x² - 4x - 3x + 4

= (3x² - 4x) - (3x - 4)

= x.(3x - 4) - (3x - 4)

= (3x - 4).(x - 1)

b) x² - 6xy + 9y²

= x² - 2.x.3y + (3y)²

= (x - 3y)²

c) x² - 8x - 9

= x² - 9x + x - 9

= (x² - 9x) + (x - 9)

= x.(x - 9) + (x - 9)

= (x - 9).(x + 1)