Hi, I need to know the answer pls hurry timed test

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

Savannah is painting a striped background for a mural on a wall that is 1515 yards long. she wants a total of 9696 stripes that are all the same width. which calculation should savannah use to decide how wide to make each stripe?

Y=(x+3)(x-4)(x+1)^2 sulutions? multiplicity?