Chapter 5 Polynomials and Polynomial Functions - 5.2 Evaluate and Graph Polynomial Functions - 5.2 Exercises - Problem Solving - Page 343: 55

$1998$

We are given the function: $$Sf(t)=-0.0076t^4+0.14t^3-0.62t^2+0.52t+5.5,$$ where $t\geq 0$. We graph the function $S$ and the line $y=8$, then find their first intersection: $$(6.729,8)$$ It follows that the first year when the number of participants was greater than $8$ million was $1992+6=1998$.