a: \(=\dfrac{12+8-3}{12}\cdot\left(\dfrac{16-15}{20}\right)^2\)
\(=\dfrac{17}{12}\cdot\dfrac{1}{400}=\dfrac{17}{4800}\)
b: \(=\dfrac{4}{9}:\dfrac{7+4-9}{18}=\dfrac{4}{9}\cdot\dfrac{18}{2}=4\)
c: \(=\dfrac{3+3^2\cdot2-3^3\cdot2}{3^2+3^3-3^4}=\dfrac{3\left(1+3\cdot2-3^2\cdot2\right)}{3^2\left(1+3-3^2\right)}\)
\(=\dfrac{1}{3}\cdot\dfrac{1+6-12}{4-9}=\dfrac{1}{3}\)
d: \(=\dfrac{5^{10}\cdot7^3\left(1-7\right)}{5^9\cdot7^3\left(1+2^3\right)}=\dfrac{5\cdot\left(-6\right)}{9}=-\dfrac{10}{3}\)