phân tích đa thức thành nhân tử
a)x2+4x+4 b)x2-1 c)x2+2x d)2x2_xy+4x-2y e)3x2-12
a) x2 + 4x + 4 = x2 + 2.2.x + 22 = ( x + 2 )2
b) x2 - 1 = ( x - 1 )( x + 1 )
c) x2 + 2x = x ( x + 2 )
d) 2x2 - xy + 4x - 2y = x ( 2x - y ) + 2( 2x - y ) = ( x + 2 )( 2x - y )
e) 3x2 - 12 = 3( x - 2 )( x + 2 )
a) x2 + 4x + 4 = x2 + 2.2.x + 22 = ( x + 2 )2
b) x2 - 1 = ( x - 1 )( x + 1 )
c) x2 + 2x = x ( x + 2 )
d) 2x2 - xy + 4x - 2y = x ( 2x - y ) + 2( 2x - y ) = ( x + 2 )( 2x - y )
e) 3x2 - 12 =3(x-2)(x+2)
a) x2+4x+4
= x2+4x+2
=(x+2)2
b)x2-1
=x2-12(có thể bỏ bước)
=(x-1)(x+1)
c)x2+2x
=x(x+2)
d)2x2-xy+4x-2y
=(2x2+4x)-(xy+2y)
=2x(x+2)-y(x+2)
=(x+2)(2x-y)
e)3x2-12
=3(x2-22)
=3(x-2)(x+
2)
a)x2+4x+4=x2+2.2.x+22=(x+2)2
b)x2-1=(x-1)(x+1)
c)x2+2x=x(x+2)
d)2x2-xy+4x-2y=(2x2+4x)-(xy+2y)=2x(x+2)+y(x+2)=(2x+y)(x+2)
e)3x2-12=3(x2-4)=3(x2-22)=3(x-2)(x+2)