若x-y=2,x2-y2=10,则x+y=_______.

更新时间：2022-05-28 10:19:26 70次访问

解：

x²-y²=10

(x+y)(x-y)=10

将 x-y=2 代入上式：

2(x+y)=10

x+y=5

(8xy2-6x2y)÷(-2x)

=-4y²+3xy

=3xy-4y²

x+y

=(x+y)(x-y)÷(x-y)

=(x²-y²)÷(x-y)

=10÷2

=5

//

(8xy²-6x²y)÷(-2x)

=2xy(4y-3x)÷(-2x)

=-y(4y-3x)

=y(3x-4y)