Question

Which of the following is the solution of log ( base x + 3) 0.001 = –3

Answer 1

5,7, 13, 0r 15 are choices. please show me steps

Answer 2

Use the definition of log.
log(base b) x = y means b^y = x

Here you have base = x + 3, so
(x + 3)^-3 = 0.001, but 0.001 = 10^-3, so
(x + 3)^-3 = 10^-3
If two powwers are equal and their exponents are equal, then the bases must be equal.
x + 3 = 10
x = 7