Question

已知m分之一加n分之一等于，m加n分之七，求，m分之n加n分之m的值。

Answer 1

1/m+1/n=7/(m+n)
(n+m)²=7mn
n²+m²+2mn=7mn
n²+m²=5mn

n/m+m/n
=(n²+m²)/(mn)
=5mn/(mn)
=5