pre calculus
posted by James .
Use properties of logarithms to find the exact value of the expression
log_7 (343 * 7^15)

log_{7} (343*7^15)
= log_{7} 343 + log_{7} 7^15
= log_{7} 7^3 + 15log_{7}7
= 3log_{7}7 + 15log_{7}7
= 3(1) + 15(1)
= 18