= ( x² - 4y² ) - ( 2x + 4y )

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

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

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

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

= \(-\left(x^2+4xy+4y^2\right)\)

= \(-\left(x+2y\right)^2\)

a) \(4x^3y^2-8x^2y+12xy^2=4xy\left(x^2y-2x+3y\right)\)

b) \(3x^2-6xy-5x+10y=3x\left(x-2y\right)-5\left(x-2y\right)=\left(x-2y\right)\left(3x-5\right)\)

c) \(x^2-49+4y^2-4xy=\left(x-2y\right)^2-49=\left(x-2y-7\right)\left(x-2y+7\right)\)

d) \(x^2-6x-16=\left(x^2-6x+9\right)-25=\left(x-3\right)^2-25=\left(x-3-5\right)\left(x-3+5\right)=\left(x-8\right)\left(x+2\right)\)

a) 

b) 

c) 

d) 

a) \(4x^3y^2-8x^2y+12xy^2=4xy.x^2y-4xy.2x+4xy.3y=4xy\left(x^2y-2x+3y\right)\)

b) \(3x^2-6xy-5x+10y=\left(3x^2-6xy\right)-\left(5x-10y\right)=3x\left(x-2y\right)-5\left(x-2y\right)=\left(x-2y\right)\left(3x-5\right)\)

c) \(x^2-49+4y^2-4xy=\left(x^2-4xy+4y^2\right)-49=\left(x-2y\right)^2-7^2=\left(x-2y-7\right)\left(x-2y+7\right)\)

d) \(x^2-6x-16=\left(x^2-8x\right)+\left(2x-16\right)=x\left(x-8\right)+2\left(x-8\right)=\left(x-8\right)\left(x+2\right)\)

\(a,=\left(x-2y\right)\left(x+2y\right)-2\left(x-2y\right)=\left(x-2y\right)\left(x+2y-2\right)\\ b,=\left(x^2+3y\right)^2-1=\left(x^2+3y-1\right)\left(x^2+3y+1\right)\)

\(b)x^4+6x^2y+9y^2-1\\=(x^4+6x^2y+9y^2)-1\\=(x^2+3y)^2-1\\=(x^2+3y-1)(x^2+3y+1)\\a) x^2-2x+4y^2+4y\\=(x^2-4y^2)-(2x-4y)\\=(x-2y)(x+2y)-2(x-2y)\\=(x-2y)(x+2y-2)\)

x² - 4xy + 4y² - z² + 2zt - t²

= (x² - 4xy + 4y²) - (z² - 2zt + t²)

= (x - 2y)² - (z - t)²

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

B

Đúng k bạn

\(\left(x^2+4y^2-20\right)^2-16\left(xy-4\right)^2=\left(x^2+4y^2-20\right)^2-\left(4xy-16\right)^2=\left(x^2+4y^2-20-4xy+16\right)\left(x^2+4y^2-20+4xy-16\right)=\left[\left(x-2y\right)^2-4\right]\left[\left(x+2y\right)^2-36\right]=\left(x-2y-2\right)\left(x-2y+2\right)\left(x+2y-6\right)\left(x+2y+6\right)\)

cảm ơn nha