Question

因式分解急急急

12乘y的二次方减3乘y的二次方。 （2x+y）平方减（x+2y)平方

Answer 1

答：
(12y²-3)y²
=3(4y²-1)y²
=3y²(2y-1)(2y+1)

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

Answer 2

第一题好奇怪啊，难道不是12乘x的二次方？
(1)12x²-3y²

=3(4x²-y²)
=3(2x+y)(2x-y)
(2)(x+y)²-(x+2y)²
=(2x+y+x+2y)(2x+y-x-2y)
=3(x+y)(x-y)

Answer 3

(12y^2-3)y^2=3(4y^2-1)y^2=3y^2[(2y)^2-1]=3y^2(2y-1)(2y+1)

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