若x-y=2,x²-y²=10,则3x-y=
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/01 18:59:50
若x-y=2,x²-y²=10,则3x-y=
若x-y=2,x²-y²=10,则3x-y=
若x-y=2,x²-y²=10,则3x-y=
解
x²-y²=10
(x-y)(x+y)=10
∵x-y=2 ①
2(x+y)=10
∴x+y=5 ②
①×2+②得:3x-y=9
若x-y=2,x²-y²=10,则3x-y=
若x-y=2,x²-y²=10,则3x-y=
若x-y=2,x²-y²=10,则3x-y=
解
x²-y²=10
(x-y)(x+y)=10
∵x-y=2 ①
2(x+y)=10
∴x+y=5 ②
①×2+②得:3x-y=9