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

2: \(=x\left(x+b\right)+a\left(x+b\right)=\left(x+b\right)\left(x+q\right)\)

3: \(=a\left(x+1\right)-b\left(x+1\right)+c\left(x+1\right)\)

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

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

Bài 2: 

a: \(3x^2-3xy=3x\left(x-y\right)\)

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

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

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

ỳtct7ct7c7c7t79tc9

a) Ta có : x² - y² - 2x + 2y

= (x² - y²) - (2x - 2y)

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

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

a, x² - y² - 2x + 2y

= ( x² - y² ) - ( 2x - 2y )

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

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

hình như em ghi sai đề rồi em nhé vì câu a không cũng 1 dạng sẽ không đưa về hằng đẳng thức được!

Đề bài là gì sao không ghi rõ?? 

a: \(y^2-9-x^2+6x\)

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

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

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

b: \(25-4x^2-4xy-y^2\)

\(=25-\left(4x^2+4xy+y^2\right)\)

\(=25-\left(2x+y\right)^2=\left(5-2x-y\right)\left(5+2x+y\right)\)

c: \(x^2-xz+4y^2-2yz+4xy\)

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

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

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

d: \(3x^2+6xy-48z^2+3y^2\)

\(=3\left\lbrack x^2+2xy+y^2-16z^2\right\rbrack\)

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

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

e: \(x^2-z^2+4y^2-4t^2-4xy+4zt\)

\(=x^2-4xy+4y^2-z^2+4zt-4t^2\)

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

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

f: \(x^3+2x^2y+xy^2-16x\)

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

\(=x\left\lbrack\left(x+y\right)^2-16\right\rbrack\)

=x(x+y+4)(x+y-4)