Pls help i only need the answers

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

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

Abag contains 4 red, 7 blue and 5 yellow marbles. event a is defined as drawing a yellow marble on the first draw and event b is defined as drawing a blue marble on the second draw. if two marbles are drawn from the bag, one after the other and not replaced, what is p(b|a) expressed in simplest form? a. 7/16 b. 7/15 c. 14/16 d. 14/15