1, \(5x^2+10x+5-5y^2=5\left(x^2+2x+1-y^2\right)\)

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

2, \(3x^3+6x^2+3x-12xy^2=3x\left(x^2+2x+1-4y^2\right)\)

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

bạn có thể viết rõ hơn ko

rồi bạn

ghytyyj

Trả lời:

7, 49y² - x² + 6x - 9

= 49y² - ( x² - 6x + 9 )

 = ( 7y )² - ( x - 3 )²

= ( 7y - x + 3 ) ( 7y - x - 3 )

8, sửa đề: 25x² - 4y² - 4y - 1

= 25x² - ( 4y² + 4y + 1 )

= ( 5x )² - ( 2y + 1 )

= ( 5x - 2y - 1 ) ( 5x + 2y + 1 )

9, 4x² - y² + 8y - 16

= 4x² - ( y² - 8y + 16 )

= ( 2x )² - ( y - 4 )²

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

a, \(49y^2-x^2+6x-9=49y^2-\left(x-3\right)^2=\left(7y-x+3\right)\left(7y+x-3\right)\)

b, đề sai rồi bạn 

c, \(4x^2-y^2+8y-16=4x^2-\left(y-4\right)^2=\left(2x-y+4\right)\left(2x+y-4\right)\)

Trả lời:

1, 15x + 15y = 15 ( x + y )

2, 8x - 12y = 4 ( 2x - 3y )

3, xy - x = x ( y - 1 )

4, x² + x = x ( x + 1 )

5, 3x²y - 8xy² = xy ( 3x - 8y )

6, 6x - 12xy - 18x² = 6x ( 1 - 2y - 3x )

1) 15x + 15y = 15(x + y)

2) 8x - 12y = 4(2x - 3y)

3) xy - x = x(y - 1)

4) x² + x = x(x + 1) 

5) 3x²y - 8xy² = xy(3x - 8y)

6) 6x - 12xy - 18x² = 6x(1 - 2y - 3x) 

1/   \(4x^2-12xy+9y^2=\left(2x\right)^2-2.2.3xy+\left(3y\right)^2\)

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

2/   \(x^3-y^6=x^3-\left(y^2\right)^3\)

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

Làm tạm 2 phần đợi mik xíu

4x² - 12xy + 9y² = ( 2x )² - 2.2x.3y + ( 3y )² = ( 2x - 3y )²

x³ - y⁶ = x³  - ( y² )³ = ( x - y² )( x² + xy² + y⁴ )

x⁶ - 6x⁴ + 12x² - 8 = ( x² )³ - 3.(x²)².2 + 3.x².2² - 2³ = ( x² - 2 )³

( x² + 4y² - 5 )² - 16( x²y² + 2xy + 1 ) = ( x² + 4y² - 5 )² - 4²( xy + 1 )²

                                                            = ( x² + 4y² - 5 )² - ( 4xy + 4 )²

                                                            = [ ( x² + 4y² - 5 ) - ( 4xy + 4 ) ][ ( x² + 4y² - 5 ) + ( 4xy + 4 ) ]

                                                            = ( x² + 4y² - 5 - 4xy - 4 )( x² + 4y² - 5 + 4xy + 4 )

                                                            = [ ( x² - 4xy + 4y² ) - 9 ][ ( x² + 4xy + 4y² ) - 1 ]

                                                            = [ ( x - 2y )² - 3² ][ ( x + 2y )² - 1² ]

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

( a + b )³ - ( a³ + b³ ) = a³ + 3a²b + 3ab² + b³ - a³ - b³

                                  = 3a²b + 3ab²

                                  = 3ab( a + b )

a)\(6x-9-x^2\)

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

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

b)\(x^2+4y^2+4xy\)

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

c)\(x^2+8x+16\)

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

d)\(9x^2-12xy+4y^2\)

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

e)\(-25x^2y^2+10xy-1\)

\(=-\left(25x^2y^2-10xy+1\right)\)

\(=-\left(5xy-1\right)^2\)

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

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

j)\(x^2+6x+9\)

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

h)\(9x^2-6x+1\)

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

#H

a, 6x - 9 - x² = - x² + 6x - 9 = - (x² - 6x + 9) = - (x - 3)²

b, x² + 4y² + 4xy = x² + 2. x . 2y + (2y)² = (x + 2y)²

c, x² + 8x + 16 = x² + 2 . x . 4 + 4² = (x + 4)²

d, 9x² - 12xy + 4y² = (3x)² - 2 . 3x . 2y + (2y)² = (3x - 2y)²

e, - 25x²y² + 10xy - 1 = - (25x²y² - 10xy + 1) = - [(5xy)² - 2 . 5xy + 1] = - (5xy - 1)²

f, 4x² - 4x + 1 = (2x)² - 2 . 2x + 1 = (2x - 1)²

j, x² + 6x + 9 = x² + 2 . x . 3 + 3² = (x + 3)²

h, 9x² - 6x + 1 = (3x)² - 2 . 3x + 1 = (3x - 1)²