Nhận xét nào sau đây là sai?

A:Sự oxi hóa chậm là quá trình oxi hóa có kèm theo tỏa nhiệt nhưng không phát sáng

B:Oxi là chất oxi hóa trong các phản ứng hóa học.

C:Sự cháy là sự oxi hóa có kèm theo tỏa nhiệt và không phát sáng.

D:Sự oxi hóa là quá trình tác dụng của một chất với oxi.

# HOK TỐT #

Nguyễn Thanh Hằng giúp vs !!!

      \(x^3+4x^2+4x+3\)

\(=x^3+3x^2+x^2+3x+x+3\)

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

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

      \(x^2-y^2+4y-4\)

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

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

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

      \(x^4+x^3y-xy^3-y^4\)

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

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

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

Chúc bạn học tốt.

1. x² - 16 - 4xy + 4y²

= ( x² - 4xy + 4y² ) - 16

= ( x - 2y )² - 4²

= ( x - 2y - 4 )( x - 2y + 4 )

2. 4x² + 4x - 3

= ( 4x² + 4x + 1 ) - 4

= ( 2x + 1 )² - 2

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

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

3. x² - x - 12

= x² + 3x - 4x - 12

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

= ( x + 3 )( x - 4 )

4. 3x + 3y - x² - 2xy - y²

= ( 3x + 3y ) - ( x² + 2xy + y² )

= 3( x + y ) - ( x + y )²

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

5. 4y⁴ + 16 

= 4( y⁴ + 4 )

= 4( y⁴ + 4y² + 4 - 4y² )

= 4[ ( y⁴ + 4y² + 4 ) - 4y² ]

= 4[ ( y² + 2 )² - ( 2y )² ]

= 4( y² - 2y + 2 )( y² + 2y + 2 )

a,\(x^2-16-4xy+4y^2\)

\(=\left(x^2-4xy+4y^2\right)-16\)

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

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

b,\(4x^2+4x-3\)

\(=4x^2-2x+6x-3\)

\(=\left(4x^2-2x\right)+\left(6x-3\right)\)

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

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

c,\(x^2-x-12\)

\(=x^2-4x+3x-12\)

\(=\left(x^2+3x\right)-\left(4x-12\right)\)

\(=x\left(x+3\right)-4\left(x+3\right)\)

\(=\left(x-4\right)\left(x+3\right)\)

a) = x^2 - 2x + 1 + 4y^2 + 4y + 1

  = ( x - 1 )^2 + ( 2y + 1 )^2 

b) = 4x^2 + 4x +1 + 4y^2 + 4y + 1

 = ( 2x + 1 )^2 + ( 2y + 1 )^2 

c) = 9x^2 - 12x + 4 + 16y^2 - 24y + 9 

=( 3x - 2 )^2 + ( 4y - 3 )^2

d) = 4x^2 + 4xy+ y^2 + x^2 - 2xz + z^2

 = ( 2x + y )^2 + ( x - z )^2 

thang Tran làm đúng rồi

\(1.\)

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

\(2.\)

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

\(3.\)

\(10x-25-x^2+4y^2=4y^2-\left(x^2-10x+25\right)=4y^2-\left(x-5\right)^2=\left(2y+x-5\right)\left(2y-x+5\right)\)

\(4.\)

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

\(5.\)

\(4x\left(x-3\right)^2-3x^2+9x=4x\left(x-3\right)^2-3x\left(x-3\right)=\left(x-3\right)\left(4x^2-12x-3x\right)\)

a ) \(x^4+x^3+2x^2+x+1\)

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

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

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

b ) \(x^2-2x-4y^2-4y\)

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

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

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

c ) \(x^4+2x^3-4x-4\)

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

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

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

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

d ) \(x^2\left(1-x^2\right)-4-4x^2\)

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

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

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

e ) Đề bài ko rõ

f ) \(\left(1+2x\right)\left(1-2x\right)-x\left(x+2\right)\left(x-2\right)\)

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

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

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

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

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

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