Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
-4*x^2-20*x == 40-4*x^2
⇒ algebra.equations.quadratic.cancel-20*x == 40
⇒ algebra.equations.coverup.timesx == -2
Description
solve a quadratic equation without abc-formula