高三数学不等式真题
以9为底的对数9a+b =以3为底的对数9a+b (1/2)
所以9a+b=ab
b=9a/(a-1)
4a+b = 4a+9a/(a-1)4a+9+9/(a-1)= 4(a-1)+9/(a-1)+13 & gt；=根号下2(4(A-1)* 9/(A-1))+13 = 25。
所以9a+b=ab
b=9a/(a-1)
4a+b = 4a+9a/(a-1)4a+9+9/(a-1)= 4(a-1)+9/(a-1)+13 & gt；=根号下2(4(A-1)* 9/(A-1))+13 = 25。