\(=\dfrac{-3.-38}{21}.\left(-\dfrac{7}{6}\right).\left(-\dfrac{3}{19}\right)\\ =\dfrac{38}{7}.\left(-\dfrac{7}{6}\right).\left(-\dfrac{3}{19}\right)\\ =\dfrac{38.\left(-7\right)}{7.6}.\left(-\dfrac{3}{19}\right)\\ =\dfrac{-19}{3}.\left(-\dfrac{3}{19}\right)=1\)
(-3) . (-38/21) . (-7/6) . (-3/19)
= 38/7 .(-7/6). (-3/19)
= -19/3 .(-3/19)
=1