So this is going to be an exponential equation, which the format is [tex]y=ab^x[/tex] , in which a is the initial value and b is the growth/decay rate.
In this case, a is going to be 340,000 and b is going to be 107%, or 1.07, since the population is going to be increasing by 7% and the equation is now [tex]y=340000(1.07)^x[/tex] .
Now replace x with 12 and solve.
[tex]y=340000(1.07)^{12}[/tex]
Solve [tex]1.07^{12}[/tex], and then if you don't round that answer and multiply it with 340000 you get [tex]y=765745[/tex] .