Tìm x, biết:

a) \(\dfrac{3}{4}x\) - \(\dfrac{7}{12}\) = \(\dfrac{5}{6}\) - \(\dfrac{2}{3}\)

b) -\(\dfrac{5}{x}\) = \(\dfrac{20}{28}\)

c) \(2\dfrac{1}{3}\) : x = 7

d) \(\dfrac{-105}{12}\) < x < \(\dfrac{20}{7}\)

Tính:

a) \(\dfrac{-7}{8}\) . \(\dfrac{3}{5}\) - \(\dfrac{2}{5}\) . \(\dfrac{7}{8}\) + \(3\dfrac{7}{8}\)

b) -1,6 : ( 1 + \(\dfrac{2}{3}\) )

c) \(\dfrac{6}{7}\) + \(\dfrac{5}{8}\) : 5 - \(\dfrac{3}{16}\) . ( -2 )\(^2\)

d) \(\dfrac{1^2}{1.2}\) . \(\dfrac{2^2}{2.3}\) . \(\dfrac{3^2}{3.4}\) . \(\dfrac{4^2}{4.5}\)