Rút gọn phân số
a) \(\frac{-1997.1996+1}{\left(-1995\right).\left(-1997\right)+1996}\) b) \(\frac{2.3+4.6+14.21}{3.5+6.10+21.35}\)
c)\(\frac{3.7.13.37.39-10101}{505050-70707}\) d)\(\frac{\left(-5\right)^3.40.4^3}{135.\left(-2\right)^{14}\left(-100\right)}\)