nanarami_18 wrote:i know that rate of growth is y=ab^x
Actually, the rate of growth is one of the variables in the exponential-growth equation, which is what you've posted.
nanarami_18 wrote:im jus needing some help with rate of decay
Without further information (such as data points, or the value of y for given values of a and b), I see no way to determine the value of the rate of growth. Sorry.