B) 39.
39. 設log2 = a,log3=b,則log, 12 = (A)-
(D).
a+2b
1-a
luglz sath
lugs 12 = log12 = loge' they3
lig5 bylo-loga
1-a
73
8
2a+b
1-a
(B)-
(C)
l-a
a+26
2a+b
a+b
) 40. 設a、為方程式logy x = log.2的兩根,則a+a + f' = ?(A)²(B)²(7²
55
G
( ) 41. 設方程式log2(x²−5x+12)=1+log,x的根為a、b,則a+b=?(A)-5 (B)5 (C)-7
(D)7-