Tìm x biết :
1) \(\frac{x+1}{15}\)+ \(\frac{x+2}{14}\)=\(\frac{x+3}{13}\)+\(\frac{x+4}{12}\)
2) \(\frac{x+1}{2012}\)+\(\frac{x+2}{2011}\)+\(\frac{x+3}{2010}\)=\(\frac{x+4}{2009}\)+\(\frac{x+5}{2008}\)+\(\frac{x+6}{2007}\)
3)\(\frac{x-2}{2013}\)+\(\frac{x-1}{2014}\)=\(\frac{x-3}{2012}\)+\(\frac{x-4}{2011}\)
4)\(\frac{x-3}{20}\)+\(\frac{x-2}{21}\)=\(\frac{x-1}{22}\)+\(\frac{x}{23}\)
5)\(\frac{x+1}{20}\)+\(\frac{x+2}{19}\)+\(\frac{x+3}{18}\)= -3
6) \(\frac{x-1}{91}\)+\(\frac{x-2}{90}\)+\(\frac{x-3}{89}\)+\(\frac{x-4}{88}\)= 5
Ai giúp mình vs...Cả đống bài tập mà chẳng biết làm gì hết
Ai làm giúp mình sẽ tick nhé
1) \(\frac{x+1}{15}+\frac{x+2}{14}=\frac{x+3}{13}+\frac{x+4}{12}\)
\(\Leftrightarrow\frac{x+16}{15}+\frac{x+16}{14}-\frac{x+16}{13}-\frac{x+16}{12}=0\)
\(\Leftrightarrow\left(x+16\right)\left(\frac{1}{15}+\frac{1}{14}-\frac{1}{13}-\frac{1}{12}\right)=0\)
\(\Leftrightarrow x=-16\)
2)3)4) tương tự
Gợi ý : 2) cộng 3 vào cả hai vế
3)4) cộng 2 vào cả hai vế
5) \(\frac{x+1}{20}+\frac{x+2}{19}+\frac{x+3}{18}=-3\)
\(\Leftrightarrow\frac{x+21}{20}+\frac{x+21}{19}+\frac{x+21}{18}=0\)
\(\Leftrightarrow\left(x+21\right)\left(\frac{1}{20}+\frac{1}{19}+\frac{1}{18}\right)=0\)
\(\Leftrightarrow x=-21\)
6) sửa VT = 4 rồi tương tự câu 5)
