问题
解答题
计算:(1)(27
(2)(
(3)
(4)log2
|
答案
(1)原式=1-(1-4)÷3 2
=1-(-2)=3.
(2)原式=(5
-52 3
)÷53 2 1 2
=5
-5.1 6
(3)原式=lg 2×5 8 lg 50 40
=1.lg 5 4 lg 5 4
(4)原式=
×lg 1 25 lg2
×lg 1 8 lg3 lg 1 9 lg5
=
×-2lg5 lg2
×-3lg2 lg3 -2lg3 lg5
=-12.