Which equation could represent this graph?

Is a deceasing linear model or an exponential decay model likely to be a better fit for the data about remembering? ?

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)

Use the x-intercept method to find all real solutions of the equation. -9x^3-7x^2-96x+36=3x^3+x^2-3x+8