Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
(x-1)^2 == 1
⇒ algebra.equations.coverup.powerx-1 == 1 or x-1 == -1
⇒ algebra.equations.coverup.onevar.minus-leftx == 2 or x-1 == -1
⇒ algebra.equations.coverup.onevar.minus-leftx == 2 or x == 0