a) \(\frac{30}{51}\)\(-\)\(\frac{20}{52}\)\(+\)\(\frac{14}{34}-\frac{56}{91}-2\)
\(=\frac{10}{17}-\frac{5}{13}+\frac{7}{17}-\frac{8}{13}-2\)
= (\(\frac{10}{17}\)\(+\frac{7}{17}\)) \(-\)(\(\frac{5}{13}+\frac{8}{13}\)) \(-2\)
= \(1-1-2\)
=\(0-2\)
= -2
k cho mik nha