Half one is 1/2;
half three is 3/2;
Thus, if f(x) represents annual growth, f(x)/2 shows it every half-year, like this:

Written in plain text: f(x)=15/2*2^x
Answer:
x-2
Step-by-step explanation:
.98 and98% .................
Every number will have only 3 digits. In the ones place, there are 5 choices. For every choice of digit made in the ones place, there are 8 possible choices for the hundreds place (you can choose from 1-9, omitting whatever is used in the ones place), and there are 8 possible choices for the tens place (you can choose from 0-9, omitting whatever has already been used elsewhere).
So there are

such numbers.
12.
7, 14, 14pi, 7^2pi
13.
13, 26, 26pi, 13^2pi
14.
9, 18, 18pi, 9^2pi
15.
10, 20, 20pi, 10^2pi