(2)10g4 (2x+3)+log4 (4x+1)=210g45
8 次の方程式を解け。
(1)10g2x+10g2(x+3)=2
(3) 10g2(3-x)=log4(2x+18)
解答 (1) x=1
(2) x=1 (3) x=-1
9 次の不等式を解け。
(1) 210go.1 (x-1)<10go.1 (7-x)
(2) 10g10(x-3) + 10g10 x ≦1
(3) 10g2(1-x) +10g2(3-x) <1+10g23
解答 (1) 3<x<7 (2) 3<x≦5 (3) 2-√7 <x<1