\(a,=\dfrac{-3^7\cdot2^8}{2^7\cdot3^7}=-2\\ b,=\dfrac{7^3\left(-21+1\right)}{7^3\cdot2\left(7^2\cdot3-1\right)}=\dfrac{-22}{2\cdot146}=\dfrac{-11}{146}\\ c,=\dfrac{5^3\cdot3^5}{5^3\left(0,5+2,5\right)}=\dfrac{3^5}{3}=3^4=81\\ d,=\dfrac{7^3\cdot5\left(7+5\right)}{7^3\cdot5^2\left(7^2\cdot5-2\right)}=\dfrac{12}{5\cdot243}=\dfrac{4}{5\cdot81}=\dfrac{4}{405}\)



