Ta có ; \(\frac{x+1}{65}+\frac{x+2}{66}=\frac{x+3}{67}+\frac{x+4}{68}\)
\(\Leftrightarrow\left(\frac{x+1}{65}-1\right)+\left(\frac{x+2}{66}-1\right)=\left(\frac{x+3}{67}-1\right)+\left(\frac{x+4}{68}-1\right)\)
\(\Leftrightarrow\frac{x-64}{65}+\frac{x-64}{66}=\frac{x-64}{67}+\frac{x-64}{68}\)
\(\Leftrightarrow\left(x-64\right)\left(\frac{1}{65}+\frac{1}{66}-\frac{1}{67}-\frac{1}{68}\right)=0\)
Vì \(\left(\frac{1}{65}+\frac{1}{66}-\frac{1}{67}-\frac{1}{68}\right)\ne0\)nên \(x-64=0\Leftrightarrow x=64\)
Vậy nghiệm của phương trình ; \(S=\left\{64\right\}\)
\(\text{Ta có ; }\)\(\frac{x+1}{65}+\frac{x+2}{66}=\frac{x+3}{67}+\frac{x+4}{68}\)
\(\Leftrightarrow\left(\frac{x+1}{65}-1\right)+\left(\frac{x+2}{66}-1\right)=\)\(\left(\frac{x+3}{67}-1\right)+\left(\frac{x+4}{68}-1\right)\)
\(\Leftrightarrow\frac{x-64}{65}+\frac{x-64}{66}=\frac{x-64}{67}+\frac{x-64}{68}\)
\(\Leftrightarrow\left(x-64\right)\left(\frac{1}{65}+\frac{1}{66}-\frac{1}{67}-\frac{1}{68}\right)=0\)
\(\text{Vì}\)\(\left(\frac{1}{65}+\frac{1}{66}-\frac{1}{67}-\frac{1}{68}\right)\ne0\)\(\text{nên}\)\(x-64=0\Leftrightarrow x=64\)
\(\text{Vậy nghiệm của phương trình ; }S=\left\{64\right\}\)
