1/64, 4 to the -3rd power, and 1/4 to the 3rd power :)
How to get answer:
[tex]\mathrm{Apply\:exponent\:rule}:\quad \:a^b\cdot \:a^c=a^{b+c}\\4^{-6}\cdot \:4^3=\:4^{3-6}=\:4^{-3}\\\mathrm{Apply\:exponent\:rule}:\quad \:a^{-b}=\frac{1}{a^b}\\=\frac{1}{4^3}\\=\frac{1}{64}[/tex]
