$b,y^2\left(x^2+y\right)-x^2z-yz$

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

$c,3x\left(x+1\right)^2-5x^2\left(x+1\right)+7x+7$

$=3x\left(x+1\right)^2-5x^2\left(x+1\right)+7\left(x+1\right)$

$=\left(x+1\right)\left[3x\left(x+1\right)-5x^2+7\right]$

$=\left(x+1\right)\left(3x-2x^2+7\right)$

$d,x^3-27+x\left(x-3\right)$

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

$=\left(x-3\right)\left(x^2+4x+9\right)$

2xy - x^2 - y^2 + 16

2xy -x2-y2+16

=-x2+2xy-y2+16

=-(x2-2xy+y2-16)

=-[(x-y)2-16]

=16-(x-y)2

= 42-(x-y)2

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

Phân tích:

a. 21bc^2-6c-3c^3+42b

b. 12y-9c^2+36-3x^2y

c. ax-bx-cx+ay-by-cy

1 . Cứ tách hằng đẳng thức rồi rút gọn là ra , dài lắm , tớ lười

2 . a2( b - c ) + b2 ( c - a ) + c2 ( a - b )

= a2b - a2c + b2c - ab2 + c2 ( a - b )

= ab( a - b) - c( a2 - b2 ) + c2 ( a - b )

= ab( a - b) - c( a + b)( a - b) + c2 ( a - b )

= ( a - b)( ab - ac - bc + c2 )

= ( a - b)[ a( b - c) - c( b - c) ]

= ( a - b)( b - c)( a - c)

c) x2 - 6x + 5

= x2 - x - 5x + 5

= x( x - 1) - 5( x - 1)

= ( x - 1)( x - 5)

d) x4 + 64

= ( x2)2 + 2.8x2 + 82 - 16x2

= ( x2 + 8)2 - ( 4x )2

= ( x2 - 4x + 8)( x2 + 4x + 8)

1. ( x - y )3 + ( y - z )3 + ( z - x )3
2. a2( b - c ) + b2 ( c - a ) + c2 ( a - b )

3. x2 - 6x + 5

4. x4 + 64

$a,21bc^2-6c-3c^3+42b$

$=21bc^2-3c^3+42b-6c$

$=3c^2\left(7b-3c\right)+6\left(7b-3c\right)=3\left(c^2+2\right)\left(7b-3c\right)$$c,ax-bx-cx+ay-by-cy$

$=x\left(a-b-c\right)+y\left(a-b-c\right)=\left(x+y\right)\left(a-b-c\right)$Còn phần b hình như sai đề

Phân tích đa thức thành nhân tử:

a) $6x^4-11x^2+3\\$

$$b) $4x^4+3x^2-4$

c) $\left(x^2+x\right)^2-2\left(x^2+x\right)-15$

d) $\left(x^2+x\right)^2+9x^2+9x+14$

e) $\left(x-y\right)^2+4x-4y-12$

f) $\left(x+2\right)\left(x+4\right)\left(x+6\right)\left(x+8\right)+16$

g) $\left(x+2\right)\left(x+3\right)\left(x+4\right)\left(x+5\right)-24$

h) $x\left(x+4\right)\left(x+6\right)\left(x+10\right)+128$

giúp mik nha ngày mai phải nộp r

c)(x2+x)2-2(x2+x)-15

đặt x2+x=a ta có

a2-2a-15

=a2+3a-5a-15

=(a2+3a)-(5a+15)

=a(a+3)-5(a+3)

=(a+3)(a-5)

thay a=x2+x

(x2+x+3)(x2+x-5)