\(\frac{x+1}{3}=\frac{12}{x+1}\)
\(\Rightarrow\left(x+1\right)^2=3.12=36\)
\(\Rightarrow\left\{\begin{matrix}x+1=-6\\x+1=6\end{matrix}\right.\)
\(\Rightarrow\left\{\begin{matrix}x=-7\\x=5\end{matrix}\right.\)
Vậy..........
tìm x biết :
a) \(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
b) \(\left(x.6\frac{2}{7}+\frac{3}{7}\right).2\frac{1}{5}-\frac{3}{7}=-2\)
c) \(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)
d) \(5\frac{8}{17}:x+\left(-\frac{4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}=\frac{4}{11}\)
e) \(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)
Tìm x;yz \(\in Q\) biết:
\(x+y=\frac{-7}{6};y+z=\frac{1}{4};z+x=\frac{1}{12}\)
tìm x, biết:
\(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)
tìm số x , biết :
a) \(\frac{2}{3}x-\frac{3}{2}x=\frac{5}{12}\)
b) \(\frac{2}{5}+\frac{3}{5}.\left(3x-3,7\right)=\frac{-53}{10}\)
c) \(\frac{7}{9}:\left(2+\frac{3}{4}x\right)+\frac{5}{9}=\frac{23}{27}\)
d) \(\frac{-2}{3}.x+\frac{1}{5}=\frac{3}{10}\)
e) \(\left|x\right|-\frac{3}{4}=\frac{5}{3}\)
f) \(\left|2x-\frac{1}{3}\right|+\frac{5}{6}=1\)
Tìm số tự nhiên x biết:
\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+.....+\frac{2}{x.\left(x+1\right)}=\frac{1999}{2001}\)
\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+....+\frac{2}{x.\left(x+1\right)}\)
Tìm x , y , z biết :
\(\frac{y+z+1}{x}=\frac{x+z2}{y}=\frac{y-3}{z}=\frac{1}{x+y+z}\)
Tìm x biết
\(\frac{2}{3}+x=\frac{-4}{5}\)\(\frac{2}{5}-x=\frac{-1}{3}\)\(1-\frac{x}{3}=1\frac{1}{2}\)\(1-\left(\frac{2x}{3}+2\right)=-1\frac{1}{3}\)Tìm x biết
\(\frac{x+2}{10^{10}}+\frac{x+2}{11^{11}}=\frac{x+2}{12^{12}}+\frac{x+2}{13^{13}}\)
