已知n分之m=7分之5,求2m-n分之3m+5n

问题描述:

已知n分之m=7分之5,求2m-n分之3m+5n

m/n=5/7
m=5n/7
所以(3m+5n)/(2m-n)
=(3*5n/7+5n)/(2*5n/7-n)
=(50n/7)/(3n/7)
=50/3