Question

Tìm x biết :

\(\dfrac{\text{x-1}}{\text{2016}}\)+\(\dfrac{\text{x-2}}{\text{2015}}\)+\(\dfrac{\text{x-3}}{2014}\)=3

Answer 1

\(\dfrac{x-1}{2016}+\dfrac{x-2}{2015}+\dfrac{x-3}{2014}=3\)

\(\Rightarrow\left(\dfrac{x-1}{2016}-1\right)+\left(\dfrac{x-2}{2015}-1\right)+\left(\dfrac{x-3}{2014}-1\right)=0\)

\(\Rightarrow\dfrac{x-2017}{2016}+\dfrac{x-2017}{2015}+\dfrac{x-2017}{2014}=0\)

\(\Rightarrow\left(x-2017\right)\left(\dfrac{1}{2016}+\dfrac{1}{2015}+\dfrac{1}{2014}\right)=0\)

Vì \(\dfrac{1}{2016}+\dfrac{1}{2015}+\dfrac{1}{2014}\ne0\) nên \(x-2017=0\Leftrightarrow x=2017\)

Answer 2

Đáp án ở đây

https://giaibaitapvenha.blogspot.com/2017/12/toan-lop-7-ai-so_25.html