Bài 1: Tính ( hợp lý nếu có thể)
A=\(\dfrac{-3}{8}\)+\(\dfrac{12}{25}\)+\(\dfrac{5}{-8}\)+\(\dfrac{2}{-5}\)+\(\dfrac{13}{25}\)
B=\(\dfrac{-3}{15}\)+(\(\dfrac{2}{3}\)+\(\dfrac{3}{15}\))
C=\(\dfrac{-5}{21}\)+(\(\dfrac{-16}{21}\)+1)
D=(\(\dfrac{-1}{6}\)+\(\dfrac{5}{-12}\))+\(\dfrac{7}{12}\)
E=\(\dfrac{1}{3}\)x\(\dfrac{4}{5}\)+\(\dfrac{1}{3}\)x\(\dfrac{6}{5}\)+\(\dfrac{2}{3}\)
F=\(\dfrac{-5}{6}\)x\(\dfrac{4}{19}\)+\(\dfrac{-7}{12}\)x\(\dfrac{4}{12}\)-\(\dfrac{40}{47}\)
Bài 2: Tìm x,biết:
a) x + \(\dfrac{2}{3}\) = \(\dfrac{4}{5}\)
b) x - \(\dfrac{2}{3}\) = \(\dfrac{7}{21}\)
c) -x - \(\dfrac{3}{4}\) =\(\dfrac{-8}{11}\)
d) \(\dfrac{11}{12}\) - (\(\dfrac{2}{5}\) + x) = \(\dfrac{2}{3}\)