The scenario is a garden.
(Assuming that the flowers don’t die at all)
3 flowers grow every once a week (x). There is 2 flowers that are already there.
For example, 3 multiplied by 5 weeks equals to 15 flowers grown and add the 2 starting flowers and will get you 17 flowers in total.
Another example, 3 multiplied by 2 weeks is 6 flowers grown and add the 2 flowers from the beginning and it will be 8 grown flowers in the garden.