\(4x^2y-8xy^2+4y^3\)
\(=4y\left(x^2-2xy+y^2\right)\)
\(=4y\left(x-y\right)^2\)
\(9-x^2+2xy-y^2\)
\(=9-\left(x^2-2xy+y^2\right)\)
\(=3^2-\left(x-y\right)^2\)
\(=\left(3-x+y\right)\left(3+x-y\right)\)
a: \(=4y\left(x^2-2xy+y^2\right)=4y\left(x-y\right)^2\)
a, 4x2y - 8xy2 + 4y3 b, 9 - x2 + 2xy - y2
= 4x2y - 4xy2 - 4xy2 + 4y3 = 9 - ( x2 - 2xy + y2 )
= 4xy ( x - y ) - 4y2 ( x - y) = 32 - ( x - y )2
= ( x - y ) 4y ( x - y ) = ( 3 - x + y ) (3+x-y)
=4y(x-y)2
