Answer:
Step-by-step explanation:
A)
A - the population after its decrease
x - the number of years in which there has been a decrease in population
Hence,
[tex]\displaystyle\\A=30000-475x\\A+475x=30000-475x+475x\\A+475x=30000\\A+475x-A=30000-A\\475x=30000-A[/tex]
Divide both parts of the equation by 475:
[tex]\displaystyle\\x=\frac{30000-A}{475}[/tex]
B)
[tex]\displaystyle\\x=\frac{30000-24300}{475} \\\\x=\frac{5700}{475}\\\\x=\frac{12*475}{475} \\\\x=12\ years[/tex]
