Write the exact answer using base-10 logarithms

Question

4^x-7=15^-10x

 

Answer 1

4^x-7 = 15^-10x

 

log(4^x-7) = log(15^-10x)

 

(x - 7)log4 = -10x log15

 

x(log4 + 10 log15) = 7 log4

 

x = (7 log4) / (log4 + 10 log15)