expand:
log base 7 a/5

condense:
g log 7

solve:
log base 7 5=1/3log base 7 (x-1)

approximate using the change of base formula (to two decimal places):
log base 3 13=?

There are a few formulas regarding loagarithms that you need to memorize:




With these facts you can solve all the problems you posted. I'll help you with the first - use the second formula above, setting b = 5.

Thank you so much!