已知X+y=12,xy=9,求（x²+3xy+2y²）/（x²y+2xy²）急

来源：学生作业学帮网编辑：学帮网时间：2024/06/01 06:49:29

x²+3xy+2y² = (X+2y)*(X+y) = (X+2y)*12
x²y+2xy² = (xy)*(X+2y) = 9*(X+2y)

约分得
（x²+3xy+2y²）/（x²y+2xy²） = (X+2y)*12/(9*(X+2y) = 12/9
)

12/9
x²+3xy+2y² = (X+2y)(X+y)
x²y+2xy² = (xy)(X+2y)
(x+2y)(x+y)/xy(x+2y)=(x+y)/xy=12/9

已知X+y=12,xy=9,求（x²+3xy+2y²）/（x²y+2xy²） 急