∵4^X=6∴X=log 4 (6) 【对数定义】= log 6 (6) / log 6 (4) 【换底公式】= 1/log 6 (4)∵9^Y=6∴y=log 9 (6) 【对数定义】= log 6 (9)/log 6 (9) 【换底公式】=1/log 6 (9)∴1/X+1/Y= 1/{1/log 6 (4)} + 1/{1/log 6...