rearrangement mechanical puzzles : Here the pieces have to be rearranged in a certain way in order to achieve a certain setup. Sometimes such the puzzles is presented in a solved state, but is easily changed into a difficult setup by a few moves by the player.
... roots of the equation. The formula reads
<math>
x=\frac{-b \pm \sqrt {b^2-4ac}}{2a}
</math>
The term b2 – 4ac is called the discriminant of the ...