Rewrite exponential expressions

**What is the expression for $f(x)$ when we rewrite $\left(\dfrac{1}{32}\right) \^{\Large x}\cdot \left(\dfrac{1}{2}\right)\^{\Large 9x-5}$ as $\left(\dfrac{1}{2}\right)\^{\Large f(x)}$** ? $f(x)=$ [[☃ expression 1]]