I really need some help...fast, test coming up!!?

Question

Write 2log9 x - 4log9 y as a single logarithm with a coefficient of 1.
I don't know how easy that is to understand so written out it's;
2 timez log9 timez x minus 4 timez log9 timez y

* If log2 A= a and log2 B=b then express log2(16 square rootAB) in terms of a and b.
that's read log2 timez A = a and log2 timez B = b.

Answer 1

2log9 x - 4log9 y =
log((9x)^2)/(9y)^4)

Log2(16√AB) =
(Log2(16) + (1/2)(Log2A + Log2B) =
(Log2(16) + (1/2)(a + b)

If Log2 means "logarithm to the base 2", then the above reduces to
4 + (1/2)(a + b)