1.a^a•b^b/(ab)^[(a+b)/2]
=a^[(a-b)/2]•b^[(b-a)/2]
=(a/b)^[(a-b)/2]
因为 a>b>0,
所以 a/b>1,(a-b)/2>0
所以(a/b)^[(a-b)/2]>1
即 a^a•b^b > (ab)^[(a+b)/2]
2.(x-1)(x-3)-(x-2)²
=x²-4x+3-(x²-4x+4)
=-1