Ta có

a,    x²-x-y²-y

=x²-y²-(x+y)

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

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

b,   x²-2xy+y²-z²

=(x-y)²-z²

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

con bai 32, 33 neu ban tra loi duoc minh h them

nhanh nha

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

\(9-x^2+2xy-y^2\)

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

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

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

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

\(b,=\left(a-1\right)^2-1-\left(2b+1\right)^2-1=\)

\(c,=\left(a-b\right)\left(a+b\right)-5\left(a+b\right)=\left(a+b\right)\left(a-b-5\right)\)

a,( x² + 2xy + y² ) -25

=( x + y )² - 5²

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

b, 

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

(x-y).(x+y)-(x-y).1

(x-y).(x+y-1)

=(x²-y²)-(x+y)

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

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

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

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

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

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

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

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

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

x^2-2xy+y^2-9z^2

=(x-y)^2-9z^2

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

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

a) 7xy^2+5x^2y

= xy(7y+5x)

b) x^2+2xy+y^2-11x-11y

= (x^2+2xy+y^2)-(11x+11y)

=(x+y)^2-11(x+y)

=(x+y)(x+y-11)

a) 7xy² + 5x²y

= xy ( 7y + 5x )

b) x² + 2xy + y² - 11x - 11y

= ( x² + 2xy + y² ) - ( 11x + 11y )

= ( x + y )² - 11 ( x + y )

= ( x + y )( x + y - 11 )

1 + 2xy - x² - y²

= 1 - x² + 2xy - y²

= 1 - ( x² - 2xy + y² )

= 1 - ( x - y )²

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

a, = (xy-y^2) + (2x-2y) = y(x-y) + 2.(x-y) = (x-y).(y+2) 

b, = (x+y)^2 - 9 = (x+y-3).(x+y+3)

\(xy-y^2-2x-2y\)   

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

=y(x-y).2(x-y)

=(x-y).(y-2)

camr ơn bạn nha