Exercise algebra.equations.quadratic.no-abc
Description
solve a quadratic equation without abc-formula
Derivation
1/4*(17-x^2) == 2
⇒ algebra.equations.coverup.times17-x^2 == 8
⇒ algebra.equations.coverup.onevar.minus-rightx^2 == 9
⇒ algebra.equations.coverup.powerx == 3 or x == -3