来自甘霖的问题
【急】求数学题详细解答过程21lg20/3-lg7+21lg3+lg7/4(lg5)^2+lg2*lg5+lg2
【急】求数学题详细解答过程
21lg20/3-lg7+21lg3+lg7/4
(lg5)^2+lg2*lg5+lg2
1回答
2020-07-3000:18
【急】求数学题详细解答过程21lg20/3-lg7+21lg3+lg7/4(lg5)^2+lg2*lg5+lg2
【急】求数学题详细解答过程
21lg20/3-lg7+21lg3+lg7/4
(lg5)^2+lg2*lg5+lg2
1.原式=21(lg20/3+lg3)-lg7+lg7-lg4
=21lg20-2lg2
=21(2lg2+lg5)-2lg2
=21(lg2+lg5)+21lg2-2lg2
=21+19lg2
2.原式=lg5(lg5+lg2)+lg2
=lg5+lg2
=1