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

\(4a^4+b^4\)

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

\(=\left[\left(2a^2\right)^2+4a^2b^2+\left(b^2\right)^2\right]-4a^2b^2\)

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

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

\(A=x^2-y^2+7x+7y\)

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

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

\(B=4x^3-4x^2+x\)

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

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

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

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

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

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

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

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

\(xy-3x-2y+6=x\left(y-3\right)-2\left(y-3\right)=\left(y-3\right)\left(x-2\right)\)

\(x^2-6xy-4z^2+9y^2=\left(x-3y\right)^2-\left(2z\right)^2=\left(x-3y-2z\right)\left(x-3y+2z\right)\)

b: Ta có: \(xy-3x-2y+6\)

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

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

c: Ta có: \(x^2-6xy+9y^2-4z^2\)

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

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

a) = (x - 4y)(x + 1)

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

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

c) = x^2(x + 3) - 7x(x + 3) + 9(x + 3)

= (x + 3)(x^2 - 7x + 9)

a: \(x^2-4xy+x-4y\)

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

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

b: \(x^2-6xy+9y^2-4\)

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

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

\(a,4x^2-4x+1\\ =\left(2x\right)^2-2.2x+1^2=\left(2x-1\right)^2\\ c,x^2-6xy-25z^2+9y^2\\ =\left(x^2-2.x.3y+9y^2\right)-\left(5z\right)^2\\ =\left(x-3y\right)^2-\left(5z\right)^2\\ =\left(x-3y-5z\right)\left(x-3y+5z\right)\)

Xem lại đề ý b

b: Ta có: \(xy-3x-2y+6\)

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

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

\(a,15x-5xy\\ =5x\left(3-y\right)\\ b,\left(x^2+1\right)^2-4x^2\\ =\left(x^2-x+1\right)\left(x^2+x+1\right)\\ c,x^2-10x-9y^2+25\\ =\left(x-5\right)^2-9y^2\\ =\left(x-9y-5\right)\left(x+9y-5\right)\)

hé lu ông zà

a) 5x(3 - y)

b) (x² - x + 1)(x² + x + 1)

c) (x - 9y - 5)(x + 9y - 5)

a: =x(x-5)

a) \(=x\left(x-5\right)\)

b) \(=\left(x+3y-3y\right)\left(x+3y+3y\right)=x\left(x+6y\right)\)

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

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

= x(x+6y)

b, (\(x^2\) - \(xy\) ) + (\(x-y\))

= (\(x-y\)).\(x\) + (\(x-y\))

= (\(x-y\)).(\(x\) + 1)

c, \(x^2\) - 2\(x\) - 15

= (\(x^2\) - 2\(x\) + 1) - 16

= (\(x\) - 1)² - 4²

= (\(x-1-4\)).(\(x-1+4\))

= (\(x-5\)).(\(x+3\))

d, 2\(x^2\) + 3\(x\) - 5

= 2\(x^2\) - 2 + 3\(x\) - 3

= 2.(\(x^2\) - 1) + 3.(\(x-1\))

= 2.(\(x-1\)).(\(x\) + 1) + 3.(\(x-1\))

= (\(x-1\)).(2\(x\) + 2  + 3)

= (\(x\) -1).(2\(x\) + 5)

a) \(A=x^2-6x+9-9y^2\)

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

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

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

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

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

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

a, \(A=\left(x-3\right)^2-9y^2=\left(x-3-3y\right)\left(x-3+3y\right)\)

b, \(B=\left(x-1\right)^3+2\left(x-1\right)\left(x+1\right)=\left(x-1\right)\left[\left(x-1\right)^2+2\left(x+1\right)\right]\)

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