(1)x2+6x+(9 )=( x+3 )^2;
(2)x2-( 4xy )+4y2=( x-2y )^2;
(3)a2-5a+(25/4 )=( x-5/2 )^2;
(4)4m2-12mn+(9n²/4 )=( 2m-3n/2 )²
2.下列各式中,能用完全平方公式分解因式的有( ② ④)
①9a2-1; ②x2+4x+4; ③m2-4mn+n2; ④-a2-b2+2a
(1)x2+6x+(9 )=( x+3 )^2;
(2)x2-( 4xy )+4y2=( x-2y )^2;
(3)a2-5a+(25/4 )=( x-5/2 )^2;
(4)4m2-12mn+(9n²/4 )=( 2m-3n/2 )²
2.下列各式中,能用完全平方公式分解因式的有( ② ④)
①9a2-1; ②x2+4x+4; ③m2-4mn+n2; ④-a2-b2+2a