\(a,\dfrac{3^{43}+3^4}{3^{39}+1}\)
\(=\dfrac{3^4\cdot\left(3^{39}+1\right)}{3^{39}+1}\)
\(=3^4\)
\(=81\)
\(b,\dfrac{3^{10}.11+3^{10}.5}{3^9.2^4}\)
\(=\dfrac{3^{10}\left(11+5\right)}{3^9.2^4}\)
\(=\dfrac{3^{10}.16}{3^9.2^4}\)
\(=\dfrac{3^{10}.2^4}{3^9.2^4}=3\)