Question

[(x+2y)的平方-(x+y)(x-y)-5y的平方]除以(2x)

[(x+2y)的平方-(x+y)(x-y)-5y的平方]除以(2x)
[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除以(4x)
[(2x+y)的平方-（-y+2x）(y+2x)]除以(2y)
help me!!!!!

Answer 1

x^2=x的平方 ‘/’为除以
[(x+2y)^2-(x+y)(x-y)-5y^2]/(2x)=[(x^2+4xy+4y^2)-(x^2-y^2)-5y^2]/(2x)
=[4xy]/(2x)=2y
[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]/(4x)=[9x^2-4y^2-(5x^2-2xy+10xy-4y^2)]/(4x)
=(4x^2-8xy)/(4x)=x-2y
[(2x+y)^2-（-y+2x）(y+2x)]/(2y)=[4x^2+4xy+y^2-(4x^2-y^2)]/(2y)
=(4xy+2y^2)/(2y)=2x+y