若a/b=c/d=e/f=2/3,求2a-c+3e/2b-d+3f的值
问题描述:
若a/b=c/d=e/f=2/3,求2a-c+3e/2b-d+3f的值
答
依题意设 a/b=c/d=e/f=2/3=k,则 a=kb.c=kd,e=kf
原式=(2a-c+3e)/(2b-d+3f)
=(2kb-kd+3kf)/(2b-d+3f)
=(2b-d+3f)k/(2b-d+3f)
=k
=2/3