Question

A computer cpu at 33mHz doubles every 18 month, using exponents how would show the answers after it doubles 3 times

Answer 1

If 33mHz doubled 3 times,
33+33=66
66+66=132
132+132=264

Answer 2

if something doubles, meaning it has a growth rate of 100%, like say hmmmmm, your flowers in the garden are hmmm 25, next morning they're 50, they doubled, their rate of growth is 100%, meaning the next morning they are 100% more than the day before.

if they have doubled 3 times, that means 18+18+18 months have passed, or 54 months.

$\bf \textit{Periodic/Cyclical Exponential Growth} \\\\ A=P(1 + r)^{\frac{t}{c}}\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{initial amount}\to &33\\ r=rate\to 100\%\to \frac{100}{100}\to &1.00\\ t=\textit{elapsed time}\to &54\\ c=period\to &18 \end{cases} \\\\\\ A=33(1 + 1)^{\frac{54}{18}}\implies A=33(2)^{\frac{54}{18}}$

of course 54/18 is 3.