When you multiple an exponent directly to a base with an exponent, you multiply the exponents together.
For example:
[tex](x^2)^5=x^{(2*5)}=x^{10}[/tex]
[tex](3^2)^1=3^{(2*1)}=3^2=9[/tex]
[tex](x^3y^2)^4=x^{(3*4)}y^{(2*4)}=x^{12}y^8[/tex]
[tex](4x^3)^2[/tex] or [tex](4^1x^3)^2[/tex]
[tex]4^{(1*2)}x^{(3*2)}=4^2x^6=16x^6[/tex] Your answer is 16x^6