One of the five quadratics below has a repeated root. (The other four have distinct roots.) What is the repeated root?

\(\begin{align*} &-x^2 + 18x + 81 \\ &3x^2 - 6x + 9 \\ &8x^2 - 32x + 32 \\ &25x^2 - 30x - 9 \\ &x^2 - 14x + 196 \end{align*}\)

It would be great if you could help me with this.

Thanks in advance!

Guest Sep 1, 2022