`A = {2^{12} . 3^{5} - 4^{6} . 9^{2}}/{(2^{2} . 3)^{6} + 8^{4} . 3^{5}} - {5^{10} . 7^{3} - 25^{5} . 49^{2}}/{(125.7)^{3} + 5^{9} . 14^{3}}`
`A = {2^{12} . 3^{5} - (2^{2})^{6} . (3^{2})^{2}}/{2^{12} . 3^{6} + (2^{3})^{4} . 3^{5}} - {5^{10} . 7^{3} - (5^{2})^{5} . (7^{2})^{2}}/{(5^{3} . 7)^{3} + 5^{9} . (2.7)^{3}}`
`A = {2^{12} . 3^{5} - 2^{12} . 3^{4}}/{2^{12} . 3^{6} + 2^{12} . 3^{5}} - {5^{10} . 7^{3} - 5^{10} . 7^{4}}/{5^{9} . 7^{3} + 5^{9} . 2^{3} . 7^{3}}`
`A = {2^{12} . 3^{4} . (3 - 1)}/{2^{12} . 3^{4} . (3^{2} + 3)} - {5^{10} . 7^{3} . (1-7)}/{5^{9} . 7^{3} . (1 + 2^{3})}`
`A = {2^{12} . 3^{4} . 2}/{2^{12} . 3^{4} . 12} - {5^{10} . 7^{3} . (-6)}/{5^{9} . 7^{3} . 9}`
`A = {2^{13} . 3^{4}}/{2^{12} . 3^{4} . 3 . 2^{2}} - {5^{10} . 7^{3} . (-6)}/{5^{9} . 7^{3} . 9}`
`A = {2^{13} . 3^{4}}/{2^{14} . 3^{5}} - {5^{10} . 7^{3} . (-6)}/{5^{9} . 7^{3} . 9}`
`A = 1/6 + 30/9`
`A = 7/2`
$\text{Vậy}$ `A = 7/2`