r=2^(n+2), then in terms of r, 9^n=
Pick one
A) r^2/81
B) r^2/16
C) r^2
D) r/3
E) r
Questions in terms of variables can be easily solved by plugging in some values: Say n = 0   r = 2^2 = 4   and you need the value of 4^n which is 4^0 = 1   So when you put r = 4 in the options, you should get 1. Only option (A) satisfies.   Answer (r^2/16)
<result>B</result>
r=2^(n+2), then in terms of r, 9^n=