Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
-x*(2*x+10) == 20-2*x^2
⇒ algebra.equations.linear.distr-times-2*x^2-10*x == 20-2*x^2
⇒ algebra.equations.quadratic.cancel-10*x == 20
⇒ algebra.equations.coverup.timesx == -2