Question

已知实数m,n满足:m+n=10,m的3次方+n的3次方=100,求m的平方+n的平方

Answer 1

你好! m^3+n^3=（m+n)(m^2-mn+n^2) =10(m^2+n^2-mn)=100 m^2+n^2-mn=10 (1) （m+n）^2=m^2+2mn+n^2=100 (2) (1)*2+(2) 2m^2+2n^2+m^2+n^2=20+100 3(m^2+n^2)=120 m^2+n^2=40 祝你学业进步!

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