Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
8 == x^2-14*x+49
⇒ algebra.equations.linear.flipx^2-14*x+49 == 8
⇒ algebra.equations.quadratic.left-square(x-7)^2 == 8
⇒ algebra.equations.coverup.powerx-7 == sqrt 8 or x-7 == -sqrt 8
⇒ algebra.equations.coverup.onevar.minus-leftx == 7+sqrt 8 or x-7 == -sqrt 8
⇒ algebra.equations.coverup.onevar.minus-leftx == 7+sqrt 8 or x == 7-sqrt 8
⇒ algebra.equations.quadratic.simpler-sqrtx == 7+2*sqrt 2 or x == 7-2*sqrt 2