[tex]8 * 2^{3} * 2^{6} = 2^{3} * 2^{3} *2^{6} = 2^{12} \\\\81 * 3^{7} : 3^{4} = 3^{4} * 3^{7} : 3^{4} = 3^{11} : 3^{4} = 3^{7} \\\\64 * 16 : 2^{5} = 2^{6} * 2^{4} : 2^{5} = 2^{5}[/tex]