Question

Нужно упростить.
Варианты ответов:
1
2/b
1/c
0
1/a

Answer 1

$1)\frac{a-1}{a}+\frac{b-1}{b}-\frac{c-1}{c} =1-\frac{1}{a}+1-\frac{1}{b}-1+\frac{1}{c}=1-\frac{1}{a}-\frac{1}{b}+\frac{1}{c}=1-(\frac{1}{a}+\frac{1}{b}-\frac{1}{c})\\\\2)(1-(\frac{1}{a}+\frac{1}{b})- \frac{1}{c}):(\frac{1}{a}+\frac{1}{b}-\frac{1}{c})=\frac{1}{\frac{bc+ac-ab}{abc} }-1=\frac{abc}{bc+ac-ab} -1\\\\3)\frac{abc}{bc+ac-ab}-\frac{abc}{bc+ac-ab}+1=1$