已知4x-5y=0,则(x+y):(x-y)的值为( ) A.1:9 B.-9 C.9 D.-1:9
问题描述:
已知4x-5y=0,则(x+y):(x-y)的值为( )
A. 1:9
B. -9
C. 9
D. -1:9
答
设x=5k,则y=4k,根据题意有
(x+y):(x-y)=(5k+4k):(5k-4k)=9.
故选C.