How do you solve #log_x729=6#?

1 Answer
Dec 31, 2015

By trying random numbers, 3 is obviously correct. However, if the answer was not an integral, the root function has to be derived and used (through calculator).

Explanation:

We can apply the logarithmic property:

#a=log_x(x^a)#

#log_x729=log_x(x^6)#

Since #logx# is a 1-1 function for any #x>0# and #x!=1# , the logarithms can be ruled out:

#729=x^6#
#729^(1/6)=(x^6)^(1/6)#
#x=729^(1/6)=root(6)(729)=3#