∵（7/15)/x=(8/15)/(7x/8+15）==>(7/15)/x=(8/15)[8/(7x+120)]
==>7/(15x)=64/[15(7x+120)]
==>7/x=64/(7x+120)
==>7(7x+120)=64x
==>49x+840=64x
==>840=15x
==>56=x
∴原方程的解是x=56