There is only one real root, at x=-2, so the polynomial describing this parabola has factors of (x+2) with multiplicity 2. The y-intercept tells you the vertical stretch is 1.
The factorization is y = (x +2)².
Do 18x18 which equals 324
We can calculate the percent change dividing the change by the original amount of people attending the exhibit.
The increase is 298-152 = 146.
Then, we can calculate the percent change as:

There was a 96% increase in the number of people attending the exhibit.