P = \(2^{12}\cdot3^5-\left(2^2\right)^6\cdot3^5\cdot3\)
\(=2^{12}\cdot3^5-2^{12}\cdot3^5\cdot3\)
\(=2^{12}\cdot3^5\left(1-3\right)\)
\(=2^{12}\cdot-2\cdot3^5\)
\(=-2^{13}\cdot3^5\)
b)
\(=2^{12}\cdot\left(3^2\right)^3+\left(2^3\right)^4\cdot3^6\)
\(=2^{12}\cdot3^6+2^{12}\cdot3^6\)
\(=2\cdot2^{12}\cdot3^6\)
\(=2^{13}\cdot3^6\)