Question

Решите уравнение
1. log2 x+log7 6= log7 18

2. log9(20x-16)-log9 4=log9 18

Answer 1

1. log2 x+log7 6= log7 18
log(2)x=log(7)18-log(7)6
log(2)x=log(7)3
x=$2 ^{log(7)3}$

2. log9(20x-16)-log9 4=log9 18
ОДЗ
20x-16>0⇒20x>16⇒x>0,8
log(9)(20x-16)=log(9)4+log(9)18
log(9)(20x-16)=log(9)72
20x-16=72
20x=88
x=4,4