\(A=\dfrac{2^{12}\cdot3^5-4^6\cdot9^2}{\left(2^2\cdot3\right)^6+8^4\cdot3^5}-\dfrac{5^{10}\cdot7^3-25^5\cdot49^2}{\left(125\cdot7\right)^3+5^9\cdot14^3}\)
\(A=\dfrac{2^{12}\cdot3^5-2^{12}\cdot3^4}{2^{12}\cdot3^6+2^{12}\cdot3^5}-\dfrac{5^{10}\cdot7^3-5^{10}\cdot7^4}{125^3\cdot7^3+5^9\cdot14^3}\)
\(A=\dfrac{2^{12}\left(3^5-3^4\right)}{2^{12}\left(3^6+3^5\right)}-\dfrac{5^{10}\cdot7^3-5^{10}\cdot7^4}{5^9\cdot7^3+5^9\cdot14^3}\)
\(A=\dfrac{2^{12}\left(3^5-3^4\right)}{2^{12}\left(3^6+3^5\right)}-\dfrac{5^{10}\left(7^3-7^4\right)}{5^9\left(7^3+14^3\right)}\)
\(A=\dfrac{162}{972}-\dfrac{5\left(-2058\right)}{3087}\)
\(A=\dfrac{1}{6}-\left(-\dfrac{10}{3}\right)\)
\(A=\dfrac{7}{2}\)