Question

Can someone help me understand this question and get the answer please!! And thank youuu !!

Answer 1

Let's plug in x = -2.

`900*3^{\text{x}}\\\\=900*3^(-2)\\\\=900*(1)/(3^2)\\\\=900*(1)/(9)\\\\=(900)/(9)\\\\=100\\\\`

Therefore,
`900*3^{\text{x}}=100 \ \text{ when x = -2}`

It means the bacteria population 2 weeks ago was 100.

A week later it triples to 100*3 = 300. A week after that we're at the present time, and the population reaches 300*3 = 900.