(A)
Step-by-step explanation:
Recall that [tex]8 = 2^3[/tex] so we can write the numerator as
[tex]8^x = (2^3)^x = 2^{3x}[/tex]
so our expression becomes
[tex]\dfrac{8^x}{2^y} = \dfrac{2^{3x}}{2^y} = 2^{3x - y}[/tex]
and since [tex]3x - y = 12,[/tex]
[tex]\dfrac{8^x}{2^y} = 2^{12}[/tex]
