正数a,b是方程x²-7x＋10=0两实根,则lga+lgb的值为：麻烦你帮我解决一下,

分类: 作业答案 • 2022-01-17 15:45:59

问题描述：

答

x²-7x＋10=0
(x-5)(x-2) = 0
x1 =5
x2 =2
lga + lgb
= lg5 + lg2
= lg(5 × 2)
= lg10
= 1