Question

因式分解: m(x+y)^2 - 4m(x-y)^2

Answer 1

更新1:

I have the wer
but i don't know how to do it!!!!!

更新2:

The wer is: - m ( 3x - y )( x - 3y )

m(x+y)^2 - 4m(x-y)^2 = m [ ( x + y )^2 - 4 ( x - y )^2 ] [ Take out m as mon factor ] = m [ ( x + y ) + 2 ( x - y ) ] [ ( x + y ) - 2 ( x - y ) ] [By a^2-b^2 = ( a + b )( a - b ) ] = m ( x + y + 2x - 2y )( x + y - 2x + 2y ) = m ( 3x - y )( - x + 3y ) = - m ( 3x - y )( x - 3y )
参考: My Maths Knowledge
m(x+y)^2-4m(x-y)^2 =m[(x+y)^2-4(x-y)^2] =m{(x+y)^2-[2(x-y)]^2} =m{[x+y+2(x-y)] [x+y-2(x-y)]} =m(3x-y)(y-x) i hope it is correct....
参考: By myself
exp = m(x^2+2xy+y^2)-4m(x^2-2xy+y^2) = mx^2+2mxy+my^2-4mx^2+8mxy-4my^2 =-3mx^2+10mxy-3my^2 =-(3mx^2+10mxy+3my^2) =-m(3x^2+10xy+3y^2) =-m(3x+1)(x+3) ANS = -m(3x+1)(x+3)
参考: myself
=-3m(x+y)^2
参考: 自己计