若x+y=2,x^2-y^2=10,求4x+6的值

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若x+y=2,x^2-y^2=10,求4x+6的值若x+y=2,x^2-y^2=10,求4x+6的值若x+y=2,x^2-y^2=10,求4x+6的值x^2-y^2=(x+y)(x-y)=10x+y=

若x+y=2,x^2-y^2=10,求4x+6的值
若x+y=2,x^2-y^2=10,求4x+6的值

若x+y=2,x^2-y^2=10,求4x+6的值
x^2-y^2=(x+y)(x-y)=10
x+y=2
所以x-y=5
两式相加,的2x=2+5=7
所以4x+6=2*7+6=20

20

x^2-y^2=(x+y)(x-y)=10,故(x-y)=5,将x+y=2与x-y=5两边相加得2x=7,从而4x+6=2*7+6=20