Hello if you can please explain.

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

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

Find two consexutive odd integers such that the sum of their square is 650