first image: y = 3.02 (3.99)^x
second image: y= 0.4x^2 + 1.6x + 2.7
third image: when it rains several inches, the water level of a lake increases
fourth image: f(x) = 103.835 − 3.61981x and the correlation coefficient is -0.9093.
fifth image: p(t) = 0.52t + 3.05