Question

已知lgx=lgy+lg(x-2y),求Y/X的值

Answer 1

lgx-lgy=lg(x-2y)

lg(x/y)=lg(x-2y)

x/y=x-2y

x=yx-2y^2

(y-1)x=2y^2

x=2y^2/(y-1)

y/x=y*(y-1)/2y^2=(y-1)/2y