Ta chỉ việc tách ra thôi VD ta thấy L
2006x2005 = 2006x2004+2006x 1
Vây ta sẽ có cách làm như sau :
\(\frac{2006\cdot2005-1}{2004\cdot2006+2005}\)
\(=\frac{2006\cdot2004+2006\cdot1-1}{2004\cdot2006+2005}\)
\(=\frac{2006\cdot2004+2006-1}{2006\cdot2004+2005}\)
\(=\frac{2006\cdot2004+2005}{2004\cdot2006+2005}=1\)
\(\frac{2006\cdot2005-1}{2004\cdot2006+2005}=\frac{2006\cdot\left(2004+1\right)}{2004\cdot2006+2005}=\frac{2006\cdot2004+2006\cdot1-1}{2004\cdot2006+2005}=\frac{2006\cdot2004+2005}{2004\cdot2006+2005}=1\)
\(\frac{2006x2005-1}{2004x2006+2005}=\frac{2006x\left(2004+1\right)-1}{2004x2006+2005}\)
\(=\frac{2006x2004+2006-1}{2004x2006+2005}\)
\(=\frac{2006x2004+2005}{2004x2006+2005}\)
\(=1\)
Giải như mình là chuẩn rồi đó :)