Question

Решите уравнение log₂ (7х – 4) = 2 + log₂ 13.

Answer 1

$mathtt{log_2(7x-4)=2+log_213;~x=frac{2^{2+log_213}+4}{7}=frac{4(2^{log_213}+1)}{7}=frac{4*14}{7}=8}$

Answer 2

log₂(7x - 4) = 2 + log₂13                              ОДЗ: 7x - 4 > 0
log₂(7x - 4) = log₂4 + log₂13                                 7x > 4
log₂(7x - 4) = log₂52                                               x > 4/7
7x - 4 = 52
7x = 52 + 4
7x = 56
x = 8