[tex]7^{2012} :[5(7^{2010} )+( 9^{2} -6^{2} -1^{2011} )7^{2010} ]= \\ 7^{2012} :7^{2010} (5+9^{2}-6^{2} -1 ) \\ =7^{2012}:7^{2010}( 7^{2} ) \\ =7^{2012}:7^{2010+2} \\ =7^{2012}:7^{2012} \\ =1 \\ \\ \\ c. \\ \\ (3^{4} +3^{5} +3^{6} +3^{7}) :(2^{5} -2 ^{4} -2 ^{3} )= \\ 3^{4}(1+3+3^{2} +3^{3} ):2 ^{3} ( 2^{2} -2-1) \\ 3^{4} 2^{3} 5:2 ^{3}1= \\= 3^{4} 5 \\ =81[/tex]
