If a function is continuous on a closed interval [a, b] and takes values f(a) and f(b), then it takes any value between f(a) and f(b) at some point within (a, b).
What is the polynomial given in the problem?
The polynomial is \(f(x) = 5x^4 - 9x^2 - 19\).
What interval is used to check for a real zero in the polynomial?