Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
x^2-2*x+1 == 4
⇒ algebra.equations.quadratic.left-square(x-1)^2 == 4
⇒ algebra.equations.coverup.powerx-1 == 2 or x-1 == -2
⇒ algebra.equations.coverup.onevar.minus-leftx == 3 or x-1 == -2
⇒ algebra.equations.coverup.onevar.minus-leftx == 3 or x == -1