Step-by-step explanation:
[tex]\text{Put}\ x=-2,\ x=0\ \text{and}\ x=3\ \text{to the equation}\ y=4^x:\\\\y=4^{-2}\qquad\text{use}\ a^{-n}=\dfrac{1}{a^n}\\\\y=\dfrac{1}{4^2}=\dfrac{1}{16}\\-----------------\\\\y=4^0=1\\-----------------\\\\y=4^3=64[/tex]