# How do you write a polynomial equation of least degree given the roots -1, 1, 4, -4, 5?

$\left(x + 1\right) \left(x - 1\right) \left(x - 4\right) \left(x + 4\right) \left(x - 5\right) = 0$
$\textcolor{w h i t e}{\text{xxx}}$...or, if you multiply the terms: ${x}^{5} - 5 {x}^{4} - 10 {x}^{3} + 50 {x}^{2} + 16 x - 80 = 0$