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NV
25 tháng 12 2022

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

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

19 tháng 9 2021

\(\left(x^3+3x^2y+3xy^2+y^3-z^3\right):\left(x+y-z\right)\\ =\left[\left(x+y\right)^3-z^3\right]:\left(x+y-z\right)\\ =\left(x+y-z\right)\left[\left(x+y\right)^2+z\left(x+y\right)+z^2\right]:\left(x+y-z\right)\\ =x^2+2xy+y^2+xz+yz+z^2\)

Vậy chọn A 

19 tháng 9 2021

Cảm ơn

 

20 tháng 3 2020

a) \(\left(x-9\right)\left(x-7\right)+1\)

\(=x^2-16x+63+1\)

\(=x^2-16x+64\)

\(=\left(x-8\right)^2\)

b) \(x^3+2x^2-3x-6\)

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

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

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

c) \(x^2-y^2+xz-yz\)

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

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

d) \(x^3-x+3x^2y+y^3-y\)

botay:(

NV
16 tháng 7 2021

a.

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

\(=\left(x+1+3z\right)\left[\left(x+1\right)^2+3z\left(x+1\right)+9z^2\right]\)

\(=\left(x+3z+1\right)\left(x^2+2x+1+3zx+3z+9z^2\right)\)

b.

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

\(=\left(x-y\right)\left(x-y-z\right)\)

c.

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

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

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

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

a) Ta có: \(x^3+3x^2+3x+1-27z^3\)

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

\(=\left(x+1-3z\right)\left(x^2+2x+1+3xz+3z+9z^2\right)\)

b) Ta có: \(x^2-2xy+y^2-zx+yz\)

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

\(=\left(x-y\right)\left(x-y-z\right)\)

c) Ta có: \(x^4+4x^2-5\)

\(=x^4+4x^2+4-9\)

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

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

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

1 tháng 11 2017

a) 6x2 - 12x

= 6x(x - 2)

b) x2 + 2x + 1 - y2

= (x2 + 2x + 1) - y2

= (x + 1)2 - y2

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

c) x + y + z + x2 + xy + xz

= (x + x2) + (y + xy) + (z + xz)

= x(1 + x) + y(1 + x) + z(1 + x)

= (x + y + z)(x + 1)

d) xy + xz + y2 + yz

= (xy + xz) + (y2 + yz)

= x(y + z) + y(y + z)

= (x + y)(x + z)

e) x3 + x2 + x + 1

= (x3 + x2) + (x + 1)

= x2(x + 1) + (x + 1)

= (x2 + 1)(x + 1)

f) xy + y - 2x - 2

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

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

= (y - 2)(x + 1)

g) x3 + 3x - 3x2 - 9

= (x3 - 3x2) + (3x - 9)

= x2(x - 3) + 3(x - 3)

= (x2 + 3)(x - 3)

h) x2 - y2 - 2x - 2y

= (x2 - y2) - (2x + 2y)

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

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

i) 7x2 - 7xy - 5x = 5y

mk thấy con này sai sai ý

1 tháng 11 2017

à câu í là :7x^2-7xy-5x+5y đấy bạn

2 tháng 3 2020

1)2xy+3z+6y+xz 

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

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

2)x^4-9x^3+x^2-9x 

= x^2(x^2 + 1) - 9x(x^2 + 1)

= (x^2 + 1)(x^2 - 9x)

= x(x - 9)(x^2 + 1)

3)x^2-xy+x-y 

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

= (x + 1)(x - y)

4)xz+yz-5(x+y)

= z(x + y) - 5(x + y)

= (z - 5)(x + y)

5)3x^2-3xy-5x+5y 

= 3x(x - y) - 5(x - y)

= (3x - 5)(x - y)

6)x^2+4x-y^2+4y 

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

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

13: =x(a^3-1)-b(a-1)

=x(a-1)(a^2+a+1)-b(a-1)

=(a-1)(a^2x+a*x+x-b)

12: =(x-y)(x+y)-(x-y)

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

10: =3(x^2-4y^2)

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

7: =x^2-x-5x+5=(x-1)(x-5)

8: =x^2+3x+4x+12=(x+3)(x+4)

9: =2x^2-6x-x+3=(x-3)(2x-1)

10 tháng 7 2018

a) xy – 3x + 2y – 6

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

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

= (y - 3)(x + 2)

b) x2y + 4xy + 4y – y3

= y(x2 + 4x + 4 - y2)

= y[(x2 + 4x + 4) - y2]

= y[(x + 2)2 - y2]

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

c) x2 + y2 + xz + yz + 2xy

= (x2 + 2xy + y2) + (xz + yz)

= (x + y)2 + z(x + y)

= (x + y)(x + y + z)

d) x3 + 3x2 – 3x – 1

= (x3 - 1) + (3x2 - 3x)

= (x - 1)(x2 + x + z) + 3x(x - 1)

= (x - 1)(x2 + 4x + 1)

10 tháng 7 2018

a ) 

\(xy-3x+2y-6\)

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

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

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

b ) 

\(x^2y+4xy+4y-y^3\)

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

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

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

c ) 

\(x^2+y^2+xz+yz+2xy\)

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

\(=\left(x+y\right)\left(x+y+z\right)\)

8 tháng 8 2018

1) \(x^2-2xy+y^2-xz+yz\)

\(\Leftrightarrow\left(x^2-2xy+y^2\right)-\left(xz-yz\right)\)

\(\Leftrightarrow\left(x-y\right)^2-z\left(x-y\right)\)

\(\Leftrightarrow\left(x-y\right)\left(x-y-z\right)\)

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

\(\Leftrightarrow\left(x-y\right)\left(x+y\right)-\left(x-y\right)\)

\(\Leftrightarrow\left(x-y\right)\left(x+y+1\right)\)

8 tháng 8 2018

\(a,x^2-2xy+y^2-xz+yz\)

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

\(=\left(x-y\right)\left(x-y-z\right)\)

\(b,x^2-y^2-x+y\)

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

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

28 tháng 9 2016

c1:

x3+3x2+3x+1-27z3

=(x+1)3-(3z)3

=(x+1-3z)[(x+1)2-(x+1)3z+9z2)

=(x+1-3z)(x2+2x+1-3xz-3z+9x2)

c2:

x2-2xy+y2-xz+yz

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

=(x-y)(x-y-z)