Respuesta :

remember
(x^m)(x^n)=x^(m+n)
and
x^-m=1/(x^m)
1/2(2^3)(2^-4)=
(1/2)(2^(3-4))=
(1/2)(2^-1)=
(1/2)(1/2^1)=
(1/2)(1/2)=1/4