The exponential expression as a decimal 10 to the 7th power

For what values of b will f(x)= logbx be a decreasing function? (16 )

Christine went shopping and bought each of her six six nephews a? gift, either a video costing? $14.95 or a cd costing? $16.88. she spent ? $ 97.42 97.42 on the gifts. how many videos and how many cds did she? buy?

For the following geometric sequence, find the recursive formula. {-80, 20, -5, } i need : ')