F(t)=t^2 - 5 ; find f(t + 3)

What states a rule using variables expression term or formula

When a number is decreased by 9.9% the result is 40. what is the original number to the nearest tenth? super urgent

For a short time after a wave is created by wind , the height of the wave can be modeled using y= a sin 2pi(t) / t where a is the amplitude and t is the period of the wave in seconds. how many times over the first 5 seconds does the graph predict the wave to be 2 feet high?