- 分式计算如果3ab=a+b,4bc=b+c,5ac=a+c,求a
- 如果3ab=a+b,4bc=b+c,5ac=a+c,求abc/(ab+bc+ac)的值
- 3ab=a+b,①
4bc=b+c,②
5ac=a+c,(5a-1)c=a,c=a/(5a-1).③
把③代入②,4ab/(5a-1)=b+a/(5a-1),
4ab=5ab-b+a,ab=b-a,④
把④代入①,3b-3a=a+b,b=2a,
代入④,2a^=a,
a=0时b=c=0,分式abc/(ab+bc+ac)无意义;
a=1/2时,b=1,c=1/3,abc/(ab+bc+ac)=(1/6)/(1/2+1/3+1/6)=1/6.