1. first we determine the growth in that period of time, for which we find a difference that in 5 years there was an increase of 3,400 people
[tex]\begin{gathered} 2012=8.000\text{ people} \\ 2017=11.400\text{ people} \\ \text{the growth in 5 years } \\ 11.400-8000=3.400 \end{gathered}[/tex]now we divide that increment by the initial value, to get the percentage of increase;
[tex]\begin{gathered} 3.400/8.000=0.425\text{ percent increase in the population} \\ \end{gathered}[/tex]