试求a^b的值”的话,即a=b=2.4时,1/a-1/b =1/2 3 =7/2.4a 6b=24 ,(a-2)^2 (3b 1)^2=0,如果原题是:“若a^2 b^2 4a-6b 13=0,原式=6a-4b-5ab-4a 6b-7ab =2a 2b-12ab =2(a b)-12ab =10-288 =-278.4a