Tìm x, biết:

a) \(\frac{29}{30}\)-\((\frac{13}{23}\)+x\()\)=\(\frac{7}{69}\)

b) \(\frac{1}{2}\)+\(\frac{1}{6}\)+\(\frac{1}{12}\)+...+\(\frac{1}{x\left(x+1\right)}\)=\(\frac{2011}{2012}\)

Tìm x, y \(\in\), biết:

a) \(\frac{x}{4}\) = \(\frac{-15}{y}\) = \(\frac{z}{52}\) = \(\frac{-32}{64}\)

b) \(\frac{x}{-4}\) = \(\frac{45}{y}\) = \(\frac{8}{-12}\)

Tìm x\(\in\)Z, biết:

a)|x+1|+|x|=1

b)|x|+x=2x