Question 755373
If 3^x = 7, which is true? 
(a) x = log_7 (3)
(b) x = log_3 (7)
(c) 3 = log_x (7)
(d) 7 = log_3 (x)
(e) 7 = log_x (3)
***
3^x = 7
This is a definition of logs in exponential form:
Base(3) raised to log of the number(x)=number(7)
so (b) is the right  answer