Question

{(x-2y)^2+(x-2y)(x+2y)-2x(2x-y)}÷2x

Answer 1

原式=（x方-4xy+4y方+x方-4y方-4x方+2xy）/2x
=（-2x方-2xy）/2x
=-2x（x+y)/2x
=-（x+y)（此时x不等于0，否则原式无意义）

Answer 2

=(x²-4xy+4y²+x²-4y²-4x²+2xy)/2x
=(-2x²-2xy)/2x
=2x(-x-y)/2x
=-x-y

Answer 3

=(x²-4xy+4y²+x²-4y²-4x²+2xy)/2x
=(-2x²-2xy)/2x
=2x(-y-x)/2x
=-y-x

Answer 4

=(x²-4xy+4y²+x²-4y²-4x²+2xy)/2x
=(-2x²-2xy)/2x
=2x(-x-y)/2x
=-x-y